Update gcc crate to 0.3.48

The 'gcc' create got a couple of updates. This change imports the new
code and bumps the version to use.

Import subrepo gcc/:gcc at 6b41873be3172415efcadbff1187a3ff42428943

5 files changed, 911 insertions, 60 deletions

diff --git a/gcc/src/com.rs b/gcc/src/com.rs
new file mode 100644
index 0000000..bd8cce7
--- /dev/null
+++ b/gcc/src/com.rs
@@ -0,0 +1,125 @@
+// Copyright © 2017 winapi-rs developers
+// Licensed under the Apache License, Version 2.0
+// <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// All files in the project carrying such notice may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(unused)]
+
+use std::ffi::{OsStr, OsString};
+use std::mem::forget;
+use std::ops::Deref;
+use std::os::windows::ffi::{OsStrExt, OsStringExt};
+use std::ptr::null_mut;
+use std::slice::from_raw_parts;
+use winapi::Interface;
+use winapi::BSTR;
+use winapi::CoInitializeEx;
+use winapi::COINIT_MULTITHREADED;
+use winapi::{SysFreeString, SysStringLen};
+use winapi::IUnknown;
+use winapi::{S_OK, S_FALSE, HRESULT};
+
+pub fn initialize() -> Result<(), HRESULT> {
+    let err = unsafe { CoInitializeEx(null_mut(), COINIT_MULTITHREADED) };
+    if err != S_OK && err != S_FALSE {
+        // S_FALSE just means COM is already initialized
+        return Err(err);
+    }
+    Ok(())
+}
+
+pub struct ComPtr<T>(*mut T) where T: Interface;
+impl<T> ComPtr<T> where T: Interface {
+    /// Creates a `ComPtr` to wrap a raw pointer.
+    /// It takes ownership over the pointer which means it does __not__ call `AddRef`.
+    /// `T` __must__ be a COM interface that inherits from `IUnknown`.
+    pub unsafe fn from_raw(ptr: *mut T) -> ComPtr<T> {
+        assert!(!ptr.is_null());
+        ComPtr(ptr)
+    }
+    /// Casts up the inheritance chain
+    pub fn up<U>(self) -> ComPtr<U> where T: Deref<Target=U>, U: Interface {
+        ComPtr(self.into_raw() as *mut U)
+    }
+    /// Extracts the raw pointer.
+    /// You are now responsible for releasing it yourself.
+    pub fn into_raw(self) -> *mut T {
+        let p = self.0;
+        forget(self);
+        p
+    }
+    /// For internal use only.
+    fn as_unknown(&self) -> &IUnknown {
+        unsafe { &*(self.0 as *mut IUnknown) }
+    }
+    /// Performs QueryInterface fun.
+    pub fn cast<U>(&self) -> Result<ComPtr<U>, i32> where U: Interface {
+        let mut obj = null_mut();
+        let err = unsafe { self.as_unknown().QueryInterface(&U::uuidof(), &mut obj) };
+        if err < 0 { return Err(err); }
+        Ok(unsafe { ComPtr::from_raw(obj as *mut U) })
+    }
+}
+impl<T> Deref for ComPtr<T> where T: Interface {
+    type Target = T;
+    fn deref(&self) -> &T {
+        unsafe { &*self.0 }
+    }
+}
+impl<T> Clone for ComPtr<T> where T: Interface {
+    fn clone(&self) -> Self {
+        unsafe {
+            self.as_unknown().AddRef();
+            ComPtr::from_raw(self.0)
+        }
+    }
+}
+impl<T> Drop for ComPtr<T> where T: Interface {
+    fn drop(&mut self) {
+        unsafe { self.as_unknown().Release(); }
+    }
+}
+pub struct BStr(BSTR);
+impl BStr {
+    pub unsafe fn from_raw(s: BSTR) -> BStr {
+        BStr(s)
+    }
+    pub fn to_osstring(&self) -> OsString {
+        let len = unsafe { SysStringLen(self.0) };
+        let slice = unsafe { from_raw_parts(self.0, len as usize) };
+        OsStringExt::from_wide(slice)
+    }
+}
+impl Drop for BStr {
+    fn drop(&mut self) {
+        unsafe { SysFreeString(self.0) };
+    }
+}
+
+pub trait ToWide {
+    fn to_wide(&self) -> Vec<u16>;
+    fn to_wide_null(&self) -> Vec<u16>;
+}
+impl<T> ToWide for T where T: AsRef<OsStr> {
+    fn to_wide(&self) -> Vec<u16> {
+        self.as_ref().encode_wide().collect()
+    }
+    fn to_wide_null(&self) -> Vec<u16> {
+        self.as_ref().encode_wide().chain(Some(0)).collect()
+    }
+}
+pub trait FromWide where Self: Sized {
+    fn from_wide(wide: &[u16]) -> Self;
+    fn from_wide_null(wide: &[u16]) -> Self {
+        let len = wide.iter().take_while(|&&c| c != 0).count();
+        Self::from_wide(&wide[..len])
+    }
+}
+impl FromWide for OsString {
+    fn from_wide(wide: &[u16]) -> OsString {
+        OsStringExt::from_wide(wide)
+    }
+}
+
diff --git a/gcc/src/lib.rs b/gcc/src/lib.rs
index 85d7d22..7d19e13 100644
--- a/gcc/src/lib.rs
+++ b/gcc/src/lib.rs
@@ -57,8 +57,18 @@ use std::process::{Command, Stdio, Child};
 use std::io::{self, BufReader, BufRead, Read, Write};
 use std::thread::{self, JoinHandle};
 
+// These modules are all glue to support reading the MSVC version from
+// the registry and from COM interfaces
 #[cfg(windows)]
 mod registry;
+#[cfg(windows)]
+#[macro_use]
+mod winapi;
+#[cfg(windows)]
+mod com;
+#[cfg(windows)]
+mod setup_config;
+
 pub mod windows_registry;
 
 /// Extra configuration to pass to gcc.
@@ -81,6 +91,7 @@ pub struct Config {
     archiver: Option<PathBuf>,
     cargo_metadata: bool,
     pic: Option<bool>,
+    static_crt: Option<bool>,
 }
 
 /// Configuration used to represent an invocation of a C compiler.
@@ -187,6 +198,7 @@ impl Config {
             archiver: None,
             cargo_metadata: true,
             pic: None,
+            static_crt: None,
         }
     }
 
@@ -363,6 +375,14 @@ impl Config {
         self
     }
 
+    /// Configures whether the /MT flag or the /MD flag will be passed to msvc build tools.
+    ///
+    /// This option defaults to `false`, and affect only msvc targets.
+    pub fn static_crt(&mut self, static_crt: bool) -> &mut Config {
+        self.static_crt = Some(static_crt);
+        self
+    }
+
 
     #[doc(hidden)]
     pub fn __set_env<A, B>(&mut self, a: A, b: B) -> &mut Config
@@ -434,12 +454,13 @@ impl Config {
         let mut cfg = rayon::Configuration::new();
         if let Ok(amt) = env::var("NUM_JOBS") {
             if let Ok(amt) = amt.parse() {
-                cfg = cfg.set_num_threads(amt);
+                cfg = cfg.num_threads(amt);
             }
         }
         drop(rayon::initialize(cfg));
 
-        objs.par_iter().weight_max().for_each(|&(ref src, ref dst)| self.compile_object(src, dst));
+        objs.par_iter().with_max_len(1)
+            .for_each(|&(ref src, ref dst)| self.compile_object(src, dst));
     }
 
     #[cfg(not(feature = "parallel"))]
@@ -533,13 +554,22 @@ impl Config {
         match cmd.family {
             ToolFamily::Msvc => {
                 cmd.args.push("/nologo".into());
-                let features = env::var("CARGO_CFG_TARGET_FEATURE")
+
+                let crt_flag = match self.static_crt {
+                    Some(true) => "/MT",
+                    Some(false) => "/MD",
+                    None => {
+                        let features = env::var("CARGO_CFG_TARGET_FEATURE")
                                   .unwrap_or(String::new());
-                if features.contains("crt-static") {
-                    cmd.args.push("/MT".into());
-                } else {
-                    cmd.args.push("/MD".into());
-                }
+                        if features.contains("crt-static") {
+                            "/MT"
+                        } else {
+                            "/MD"
+                        }
+                    },
+                };
+                cmd.args.push(crt_flag.into());
+
                 match &opt_level[..] {
                     "z" | "s" => cmd.args.push("/Os".into()),
                     "1" => cmd.args.push("/O1".into()),
@@ -593,7 +623,7 @@ impl Config {
                 }
 
                 // armv7 targets get to use armv7 instructions
-                if target.starts_with("armv7-unknown-linux-") {
+                if target.starts_with("armv7-") && target.contains("-linux-") {
                     cmd.args.push("-march=armv7-a".into());
                 }
 
@@ -602,6 +632,7 @@ impl Config {
                 if target.starts_with("armv7-linux-androideabi") {
                     cmd.args.push("-march=armv7-a".into());
                     cmd.args.push("-mfpu=vfpv3-d16".into());
+                    cmd.args.push("-mfloat-abi=softfp".into());
                 }
 
                 // For us arm == armv6 by default
@@ -610,6 +641,15 @@ impl Config {
                     cmd.args.push("-marm".into());
                 }
 
+                // We can guarantee some settings for FRC
+                if target.starts_with("arm-frc-") {
+                    cmd.args.push("-march=armv7-a".into());
+                    cmd.args.push("-mcpu=cortex-a9".into());
+                    cmd.args.push("-mfpu=vfpv3".into());
+                    cmd.args.push("-mfloat-abi=softfp".into());
+                    cmd.args.push("-marm".into());
+                }
+
                 // Turn codegen down on i586 to avoid some instructions.
                 if target.starts_with("i586-unknown-linux-") {
                     cmd.args.push("-march=pentium".into());
@@ -683,7 +723,7 @@ impl Config {
 
         for &(ref key, ref value) in self.definitions.iter() {
             let lead = if let ToolFamily::Msvc = cmd.family {"/"} else {"-"};
-            if let &Some(ref value) = value {
+            if let Some(ref value) = *value {
                 cmd.args.push(format!("{}D{}={}", lead, key, value).into());
             } else {
                 cmd.args.push(format!("{}D{}", lead, key).into());
@@ -704,7 +744,7 @@ impl Config {
             cmd.arg("/I").arg(directory);
         }
         for &(ref key, ref value) in self.definitions.iter() {
-            if let &Some(ref value) = value {
+            if let Some(ref value) = *value {
                 cmd.arg(&format!("/D{}={}", key, value));
             } else {
                 cmd.arg(&format!("/D{}", key));
@@ -730,7 +770,7 @@ impl Config {
         if target.contains("msvc") {
             let mut cmd = match self.archiver {
                 Some(ref s) => self.cmd(s),
-                None => windows_registry::find(&target, "lib.exe").unwrap_or(self.cmd("lib.exe")),
+                None => windows_registry::find(&target, "lib.exe").unwrap_or_else(|| self.cmd("lib.exe")),
             };
             let mut out = OsString::from("/OUT:");
             out.push(dst);
@@ -750,7 +790,6 @@ impl Config {
                     // if hard-link fails, just copy (ignoring the number of bytes written)
                     fs::copy(&dst, &lib_dst).map(|_| ())
                 })
-                .ok()
                 .expect("Copying from {:?} to {:?} failed.");;
         } else {
             let ar = self.get_ar();
@@ -816,7 +855,7 @@ impl Config {
         for &(ref a, ref b) in self.env.iter() {
             cmd.env(a, b);
         }
-        return cmd;
+        cmd
     }
 
     fn get_base_compiler(&self) -> Tool {
@@ -846,15 +885,26 @@ impl Config {
                 for arg in args {
                     t.args.push(arg.into());
                 }
-                return t;
+                t
             })
             .or_else(|| {
                 if target.contains("emscripten") {
-                    if self.cpp {
-                        Some(Tool::new(PathBuf::from("em++")))
+                    //Windows uses bat file so we have to be a bit more specific
+                    let tool = if self.cpp {
+                        if cfg!(windows) {
+                            "em++.bat"
+                        } else {
+                            "em++"
+                        }
                     } else {
-                        Some(Tool::new(PathBuf::from("emcc")))
-                    }
+                        if cfg!(windows) {
+                            "emcc.bat"
+                        } else {
+                            "emcc"
+                        }
+                    };
+
+                    Some(Tool::new(PathBuf::from(tool)))
                 } else {
                     None
                 }
@@ -876,6 +926,7 @@ impl Config {
                     let prefix = cross_compile.or(match &target[..] {
                         "aarch64-unknown-linux-gnu" => Some("aarch64-linux-gnu"),
                         "arm-unknown-linux-gnueabi" => Some("arm-linux-gnueabi"),
+                        "arm-frc-linux-gnueabi" => Some("arm-frc-linux-gnueabi"),
                         "arm-unknown-linux-gnueabihf" => Some("arm-linux-gnueabihf"),
                         "arm-unknown-linux-musleabi" => Some("arm-linux-musleabi"),
                         "arm-unknown-linux-musleabihf" => Some("arm-linux-musleabihf"),
@@ -948,7 +999,7 @@ impl Config {
         self.get_var(name).ok().map(|tool| {
             let whitelist = ["ccache", "distcc"];
             for t in whitelist.iter() {
-                if tool.starts_with(t) && tool[t.len()..].starts_with(" ") {
+                if tool.starts_with(t) && tool[t.len()..].starts_with(' ') {
                     return (t.to_string(), vec![tool[t.len()..].trim_left().to_string()]);
                 }
             }
@@ -981,7 +1032,14 @@ impl Config {
                 if self.get_target().contains("android") {
                     PathBuf::from(format!("{}-ar", self.get_target().replace("armv7", "arm")))
                 } else if self.get_target().contains("emscripten") {
-                    PathBuf::from("emar")
+                    //Windows use bat files so we have to be a bit more specific
+                    let tool = if cfg!(windows) {
+                        "emar.bat"
+                    } else {
+                        "emar"
+                    };
+
+                    PathBuf::from(tool)
                 } else {
                     PathBuf::from("ar")
                 }
@@ -1034,7 +1092,7 @@ impl Tool {
         let family = if let Some(fname) = path.file_name().and_then(|p| p.to_str()) {
             if fname.contains("clang") {
                 ToolFamily::Clang
-            } else if fname.contains("cl") {
+            } else if fname.contains("cl") && !fname.contains("uclibc") {
                 ToolFamily::Msvc
             } else {
                 ToolFamily::Gnu
@@ -1091,7 +1149,7 @@ fn run(cmd: &mut Command, program: &str) {
     let (mut child, print) = spawn(cmd, program);
     let status = child.wait().expect("failed to wait on child process");
     print.join().unwrap();
-    println!("{:?}", status);
+    println!("{}", status);
     if !status.success() {
         fail(&format!("command did not execute successfully, got: {}", status));
     }
@@ -1104,11 +1162,11 @@ fn run_output(cmd: &mut Command, program: &str) -> Vec<u8> {
     child.stdout.take().unwrap().read_to_end(&mut stdout).unwrap();
     let status = child.wait().expect("failed to wait on child process");
     print.join().unwrap();
-    println!("{:?}", status);
+    println!("{}", status);
     if !status.success() {
         fail(&format!("command did not execute successfully, got: {}", status));
     }
-    return stdout
+    stdout
 }
 
 fn spawn(cmd: &mut Command, program: &str) -> (Child, JoinHandle<()>) {
diff --git a/gcc/src/setup_config.rs b/gcc/src/setup_config.rs
new file mode 100644
index 0000000..175b7f1
--- /dev/null
+++ b/gcc/src/setup_config.rs
@@ -0,0 +1,257 @@
+// Copyright © 2017 winapi-rs developers
+// Licensed under the Apache License, Version 2.0
+// <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// All files in the project carrying such notice may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(bad_style)]
+#![allow(unused)]
+
+use std::ffi::OsString;
+use std::ptr::null_mut;
+use winapi::Interface;
+use winapi::{LPFILETIME, ULONG};
+use winapi::S_FALSE;
+use winapi::BSTR;
+use winapi::LPCOLESTR;
+use winapi::{CLSCTX_ALL, CoCreateInstance};
+use winapi::LPSAFEARRAY;
+use winapi::{IUnknown, IUnknownVtbl};
+use winapi::{HRESULT, LCID, LPCWSTR, PULONGLONG};
+
+use com::{BStr, ComPtr};
+
+// Bindings to the Setup.Configuration stuff
+pub type InstanceState = u32;
+
+pub const eNone: InstanceState = 0;
+pub const eLocal: InstanceState = 1;
+pub const eRegistered: InstanceState = 2;
+pub const eNoRebootRequired: InstanceState = 4;
+pub const eComplete: InstanceState = -1i32 as u32;
+
+RIDL!{#[uuid(0xb41463c3, 0x8866, 0x43b5, 0xbc, 0x33, 0x2b, 0x06, 0x76, 0xf7, 0xf4, 0x2e)]
+interface ISetupInstance(ISetupInstanceVtbl): IUnknown(IUnknownVtbl) {
+    fn GetInstanceId(
+        pbstrInstanceId: *mut BSTR,
+    ) -> HRESULT,
+    fn GetInstallDate(
+        pInstallDate: LPFILETIME,
+    ) -> HRESULT,
+    fn GetInstallationName(
+        pbstrInstallationName: *mut BSTR,
+    ) -> HRESULT,
+    fn GetInstallationPath(
+        pbstrInstallationPath: *mut BSTR,
+    ) -> HRESULT,
+    fn GetInstallationVersion(
+        pbstrInstallationVersion: *mut BSTR,
+    ) -> HRESULT,
+    fn GetDisplayName(
+        lcid: LCID,
+        pbstrDisplayName: *mut BSTR,
+    ) -> HRESULT,
+    fn GetDescription(
+        lcid: LCID,
+        pbstrDescription: *mut BSTR,
+    ) -> HRESULT,
+    fn ResolvePath(
+        pwszRelativePath: LPCOLESTR,
+        pbstrAbsolutePath: *mut BSTR,
+    ) -> HRESULT,
+}}
+
+RIDL!{#[uuid(0x89143c9a, 0x05af, 0x49b0, 0xb7, 0x17, 0x72, 0xe2, 0x18, 0xa2, 0x18, 0x5c)]
+interface ISetupInstance2(ISetupInstance2Vtbl): ISetupInstance(ISetupInstanceVtbl) {
+    fn GetState(
+        pState: *mut InstanceState,
+    ) -> HRESULT,
+    fn GetPackages(
+        ppsaPackages: *mut LPSAFEARRAY,
+    ) -> HRESULT,
+    fn GetProduct(
+        ppPackage: *mut *mut ISetupPackageReference,
+    ) -> HRESULT,
+    fn GetProductPath(
+        pbstrProductPath: *mut BSTR,
+    ) -> HRESULT,
+}}
+
+RIDL!{#[uuid(0x6380bcff, 0x41d3, 0x4b2e, 0x8b, 0x2e, 0xbf, 0x8a, 0x68, 0x10, 0xc8, 0x48)]
+interface IEnumSetupInstances(IEnumSetupInstancesVtbl): IUnknown(IUnknownVtbl) {
+    fn Next(
+        celt: ULONG,
+        rgelt: *mut *mut ISetupInstance,
+        pceltFetched: *mut ULONG,
+    ) -> HRESULT,
+    fn Skip(
+        celt: ULONG,
+    ) -> HRESULT,
+    fn Reset() -> HRESULT,
+    fn Clone(
+        ppenum: *mut *mut IEnumSetupInstances,
+    ) -> HRESULT,
+}}
+
+RIDL!{#[uuid(0x42843719, 0xdb4c, 0x46c2, 0x8e, 0x7c, 0x64, 0xf1, 0x81, 0x6e, 0xfd, 0x5b)]
+interface ISetupConfiguration(ISetupConfigurationVtbl): IUnknown(IUnknownVtbl) {
+    fn EnumInstances(
+        ppEnumInstances: *mut *mut IEnumSetupInstances,
+    ) -> HRESULT,
+    fn GetInstanceForCurrentProcess(
+        ppInstance: *mut *mut ISetupInstance,
+    ) -> HRESULT,
+    fn GetInstanceForPath(
+        wzPath: LPCWSTR,
+        ppInstance: *mut *mut ISetupInstance,
+    ) -> HRESULT,
+}}
+
+RIDL!{#[uuid(0x26aab78c, 0x4a60, 0x49d6, 0xaf, 0x3b, 0x3c, 0x35, 0xbc, 0x93, 0x36, 0x5d)]
+interface ISetupConfiguration2(ISetupConfiguration2Vtbl):
+    ISetupConfiguration(ISetupConfigurationVtbl) {
+    fn EnumAllInstances(
+        ppEnumInstances: *mut *mut IEnumSetupInstances,
+    ) -> HRESULT,
+}}
+
+RIDL!{#[uuid(0xda8d8a16, 0xb2b6, 0x4487, 0xa2, 0xf1, 0x59, 0x4c, 0xcc, 0xcd, 0x6b, 0xf5)]
+interface ISetupPackageReference(ISetupPackageReferenceVtbl): IUnknown(IUnknownVtbl) {
+    fn GetId(
+        pbstrId: *mut BSTR,
+    ) -> HRESULT,
+    fn GetVersion(
+        pbstrVersion: *mut BSTR,
+    ) -> HRESULT,
+    fn GetChip(
+        pbstrChip: *mut BSTR,
+    ) -> HRESULT,
+    fn GetLanguage(
+        pbstrLanguage: *mut BSTR,
+    ) -> HRESULT,
+    fn GetBranch(
+        pbstrBranch: *mut BSTR,
+    ) -> HRESULT,
+    fn GetType(
+        pbstrType: *mut BSTR,
+    ) -> HRESULT,
+    fn GetUniqueId(
+        pbstrUniqueId: *mut BSTR,
+    ) -> HRESULT,
+}}
+
+RIDL!{#[uuid(0x42b21b78, 0x6192, 0x463e, 0x87, 0xbf, 0xd5, 0x77, 0x83, 0x8f, 0x1d, 0x5c)]
+interface ISetupHelper(ISetupHelperVtbl): IUnknown(IUnknownVtbl) {
+    fn ParseVersion(
+        pwszVersion: LPCOLESTR,
+        pullVersion: PULONGLONG,
+    ) -> HRESULT,
+    fn ParseVersionRange(
+        pwszVersionRange: LPCOLESTR,
+        pullMinVersion: PULONGLONG,
+        pullMaxVersion: PULONGLONG,
+    ) -> HRESULT,
+}}
+
+DEFINE_GUID!{CLSID_SetupConfiguration,
+    0x177f0c4a, 0x1cd3, 0x4de7, 0xa3, 0x2c, 0x71, 0xdb, 0xbb, 0x9f, 0xa3, 0x6d}
+
+// Safe wrapper around the COM interfaces
+pub struct SetupConfiguration(ComPtr<ISetupConfiguration>);
+
+impl SetupConfiguration {
+    pub fn new() -> Result<SetupConfiguration, i32> {
+        let mut obj = null_mut();
+        let err = unsafe { CoCreateInstance(
+            &CLSID_SetupConfiguration, null_mut(), CLSCTX_ALL,
+            &ISetupConfiguration::uuidof(), &mut obj,
+        ) };
+        if err < 0 { return Err(err); }
+        let obj = unsafe { ComPtr::from_raw(obj as *mut ISetupConfiguration) };
+        Ok(SetupConfiguration(obj))
+    }
+    pub fn get_instance_for_current_process(&self) -> Result<SetupInstance, i32> {
+        let mut obj = null_mut();
+        let err = unsafe { self.0.GetInstanceForCurrentProcess(&mut obj) };
+        if err < 0 { return Err(err); }
+        Ok(unsafe { SetupInstance::from_raw(obj) })
+    }
+    pub fn enum_instances(&self) -> Result<EnumSetupInstances, i32> {
+        let mut obj = null_mut();
+        let err = unsafe { self.0.EnumInstances(&mut obj) };
+        if err < 0 { return Err(err); }
+        Ok(unsafe { EnumSetupInstances::from_raw(obj) })
+    }
+    pub fn enum_all_instances(&self) -> Result<EnumSetupInstances, i32> {
+        let mut obj = null_mut();
+        let this = try!(self.0.cast::<ISetupConfiguration2>());
+        let err = unsafe { this.EnumAllInstances(&mut obj) };
+        if err < 0 { return Err(err); }
+        Ok(unsafe { EnumSetupInstances::from_raw(obj) })
+    }
+}
+
+pub struct SetupInstance(ComPtr<ISetupInstance>);
+
+impl SetupInstance {
+    pub unsafe fn from_raw(obj: *mut ISetupInstance) -> SetupInstance {
+        SetupInstance(ComPtr::from_raw(obj))
+    }
+    pub fn instance_id(&self) -> Result<OsString, i32> {
+        let mut s = null_mut();
+        let err = unsafe { self.0.GetInstanceId(&mut s) };
+        let bstr = unsafe { BStr::from_raw(s) };
+        if err < 0 { return Err(err); }
+        Ok(bstr.to_osstring())
+    }
+    pub fn installation_name(&self) -> Result<OsString, i32> {
+        let mut s = null_mut();
+        let err = unsafe { self.0.GetInstallationName(&mut s) };
+        let bstr = unsafe { BStr::from_raw(s) };
+        if err < 0 { return Err(err); }
+        Ok(bstr.to_osstring())
+    }
+    pub fn installation_path(&self) -> Result<OsString, i32> {
+        let mut s = null_mut();
+        let err = unsafe { self.0.GetInstallationPath(&mut s) };
+        let bstr = unsafe { BStr::from_raw(s) };
+        if err < 0 { return Err(err); }
+        Ok(bstr.to_osstring())
+    }
+    pub fn installation_version(&self) -> Result<OsString, i32> {
+        let mut s = null_mut();
+        let err = unsafe { self.0.GetInstallationVersion(&mut s) };
+        let bstr = unsafe { BStr::from_raw(s) };
+        if err < 0 { return Err(err); }
+        Ok(bstr.to_osstring())
+    }
+    pub fn product_path(&self) -> Result<OsString, i32> {
+        let mut s = null_mut();
+        let this = try!(self.0.cast::<ISetupInstance2>());
+        let err = unsafe { this.GetProductPath(&mut s) };
+        let bstr = unsafe { BStr::from_raw(s) };
+        if err < 0 { return Err(err); }
+        Ok(bstr.to_osstring())
+    }
+}
+
+pub struct EnumSetupInstances(ComPtr<IEnumSetupInstances>);
+
+impl EnumSetupInstances {
+    pub unsafe fn from_raw(obj: *mut IEnumSetupInstances) -> EnumSetupInstances {
+        EnumSetupInstances(ComPtr::from_raw(obj))
+    }
+}
+
+impl Iterator for EnumSetupInstances {
+    type Item = Result<SetupInstance, i32>;
+    fn next(&mut self) -> Option<Result<SetupInstance, i32>> {
+        let mut obj = null_mut();
+        let err = unsafe { self.0.Next(1, &mut obj, null_mut()) };
+        if err < 0 { return Some(Err(err)); }
+        if err == S_FALSE { return None; }
+        Some(Ok(unsafe { SetupInstance::from_raw(obj) }))
+    }
+}
+
diff --git a/gcc/src/winapi.rs b/gcc/src/winapi.rs
new file mode 100644
index 0000000..010d165
--- /dev/null
+++ b/gcc/src/winapi.rs
@@ -0,0 +1,214 @@
+// Copyright © 2015-2017 winapi-rs developers
+// Licensed under the Apache License, Version 2.0
+// <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// All files in the project carrying such notice may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(bad_style)]
+
+use std::os::raw;
+
+pub type wchar_t = u16;
+
+pub type UINT = raw::c_uint;
+pub type LPUNKNOWN = *mut IUnknown;
+pub type REFIID = *const IID;
+pub type IID = GUID;
+pub type REFCLSID = *const IID;
+pub type PVOID = *mut raw::c_void;
+pub type USHORT = raw::c_ushort;
+pub type ULONG = raw::c_ulong;
+pub type LONG = raw::c_long;
+pub type DWORD = u32;
+pub type LPVOID = *mut raw::c_void;
+pub type HRESULT = raw::c_long;
+pub type LPFILETIME = *mut FILETIME;
+pub type BSTR = *mut OLECHAR;
+pub type OLECHAR = WCHAR;
+pub type WCHAR = wchar_t;
+pub type LPCOLESTR = *const OLECHAR;
+pub type LCID = DWORD;
+pub type LPCWSTR = *const WCHAR;
+pub type PULONGLONG = *mut ULONGLONG;
+pub type ULONGLONG = u64;
+
+pub const S_OK: HRESULT = 0;
+pub const S_FALSE: HRESULT = 1;
+pub const COINIT_MULTITHREADED: u32 = 0x0;
+
+pub type CLSCTX = u32;
+
+pub const CLSCTX_INPROC_SERVER: CLSCTX = 0x1;
+pub const CLSCTX_INPROC_HANDLER: CLSCTX = 0x2;
+pub const CLSCTX_LOCAL_SERVER: CLSCTX = 0x4;
+pub const CLSCTX_REMOTE_SERVER: CLSCTX = 0x10;
+
+pub const CLSCTX_ALL: CLSCTX = CLSCTX_INPROC_SERVER |
+    CLSCTX_INPROC_HANDLER | CLSCTX_LOCAL_SERVER | CLSCTX_REMOTE_SERVER;
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct GUID {
+    pub Data1: raw::c_ulong,
+    pub Data2: raw::c_ushort,
+    pub Data3: raw::c_ushort,
+    pub Data4: [raw::c_uchar; 8],
+}
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct FILETIME {
+    pub dwLowDateTime: DWORD,
+    pub dwHighDateTime: DWORD,
+}
+
+pub trait Interface {
+    fn uuidof() -> GUID;
+}
+
+#[link(name = "Ole32")]
+#[link(name = "OleAut32")]
+extern { }
+
+extern "system" {
+    pub fn CoInitializeEx(pvReserved: LPVOID, dwCoInit: DWORD) -> HRESULT;
+    pub fn CoCreateInstance(rclsid: REFCLSID, pUnkOuter: LPUNKNOWN,
+                            dwClsContext: DWORD, riid: REFIID,
+                            ppv: *mut LPVOID) -> HRESULT;
+    pub fn SysFreeString(bstrString: BSTR);
+    pub fn SysStringLen(pbstr: BSTR) -> UINT;
+}
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct SAFEARRAYBOUND {
+    pub cElements: ULONG,
+    pub lLbound: LONG,
+}
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct SAFEARRAY {
+    pub cDims: USHORT,
+    pub fFeatures: USHORT,
+    pub cbElements: ULONG,
+    pub cLocks: ULONG,
+    pub pvData: PVOID,
+    pub rgsabound: [SAFEARRAYBOUND; 1],
+}
+
+pub type LPSAFEARRAY = *mut SAFEARRAY;
+
+macro_rules! DEFINE_GUID {
+    (
+        $name:ident, $l:expr, $w1:expr, $w2:expr,
+        $b1:expr, $b2:expr, $b3:expr, $b4:expr, $b5:expr, $b6:expr, $b7:expr, $b8:expr
+    ) => {
+        pub const $name: $crate::winapi::GUID = $crate::winapi::GUID {
+            Data1: $l,
+            Data2: $w1,
+            Data3: $w2,
+            Data4: [$b1, $b2, $b3, $b4, $b5, $b6, $b7, $b8],
+        };
+    }
+}
+
+macro_rules! RIDL {
+    (#[uuid($($uuid:expr),+)]
+    interface $interface:ident ($vtbl:ident) {$(
+        fn $method:ident($($p:ident : $t:ty,)*) -> $rtr:ty,
+    )+}) => (
+        #[repr(C)]
+        pub struct $vtbl {
+            $(pub $method: unsafe extern "system" fn(
+                This: *mut $interface,
+                $($p: $t),*
+            ) -> $rtr,)+
+        }
+        #[repr(C)]
+        pub struct $interface {
+            pub lpVtbl: *const $vtbl,
+        }
+        RIDL!{@impl $interface {$(fn $method($($p: $t,)*) -> $rtr,)+}}
+        RIDL!{@uuid $interface $($uuid),+}
+    );
+    (#[uuid($($uuid:expr),+)]
+    interface $interface:ident ($vtbl:ident) : $pinterface:ident ($pvtbl:ident) {
+    }) => (
+        #[repr(C)]
+        pub struct $vtbl {
+            pub parent: $pvtbl,
+        }
+        #[repr(C)]
+        pub struct $interface {
+            pub lpVtbl: *const $vtbl,
+        }
+        RIDL!{@deref $interface $pinterface}
+        RIDL!{@uuid $interface $($uuid),+}
+    );
+    (#[uuid($($uuid:expr),+)]
+    interface $interface:ident ($vtbl:ident) : $pinterface:ident ($pvtbl:ident) {$(
+        fn $method:ident($($p:ident : $t:ty,)*) -> $rtr:ty,
+    )+}) => (
+        #[repr(C)]
+        pub struct $vtbl {
+            pub parent: $pvtbl,
+            $(pub $method: unsafe extern "system" fn(
+                This: *mut $interface,
+                $($p: $t,)*
+            ) -> $rtr,)+
+        }
+        #[repr(C)]
+        pub struct $interface {
+            pub lpVtbl: *const $vtbl,
+        }
+        RIDL!{@impl $interface {$(fn $method($($p: $t,)*) -> $rtr,)+}}
+        RIDL!{@deref $interface $pinterface}
+        RIDL!{@uuid $interface $($uuid),+}
+    );
+    (@deref $interface:ident $pinterface:ident) => (
+        impl ::std::ops::Deref for $interface {
+            type Target = $pinterface;
+            #[inline]
+            fn deref(&self) -> &$pinterface {
+                unsafe { &*(self as *const $interface as *const $pinterface) }
+            }
+        }
+    );
+    (@impl $interface:ident {$(
+        fn $method:ident($($p:ident : $t:ty,)*) -> $rtr:ty,
+    )+}) => (
+        impl $interface {
+            $(#[inline] pub unsafe fn $method(&self, $($p: $t,)*) -> $rtr {
+                ((*self.lpVtbl).$method)(self as *const _ as *mut _, $($p,)*)
+            })+
+        }
+    );
+    (@uuid $interface:ident
+        $l:expr, $w1:expr, $w2:expr,
+        $b1:expr, $b2:expr, $b3:expr, $b4:expr, $b5:expr, $b6:expr, $b7:expr, $b8:expr
+    ) => (
+        impl $crate::winapi::Interface for $interface {
+            #[inline]
+            fn uuidof() -> $crate::winapi::GUID {
+                $crate::winapi::GUID {
+                    Data1: $l,
+                    Data2: $w1,
+                    Data3: $w2,
+                    Data4: [$b1, $b2, $b3, $b4, $b5, $b6, $b7, $b8],
+                }
+            }
+        }
+    );
+}
+
+RIDL!{#[uuid(0x00000000, 0x0000, 0x0000, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x46)]
+interface IUnknown(IUnknownVtbl) {
+    fn QueryInterface(
+        riid: REFIID,
+        ppvObject: *mut *mut raw::c_void,
+    ) -> HRESULT,
+    fn AddRef() -> ULONG,
+    fn Release() -> ULONG,
+}}
diff --git a/gcc/src/windows_registry.rs b/gcc/src/windows_registry.rs
index 08b1df5..d05fc1d 100644
--- a/gcc/src/windows_registry.rs
+++ b/gcc/src/windows_registry.rs
@@ -15,6 +15,7 @@ use std::process::Command;
 
 use Tool;
 
+#[cfg(windows)]
 macro_rules! otry {
     ($expr:expr) => (match $expr {
         Some(val) => val,
@@ -50,10 +51,119 @@ pub fn find_tool(_target: &str, _tool: &str) -> Option<Tool> {
 #[cfg(windows)]
 pub fn find_tool(target: &str, tool: &str) -> Option<Tool> {
     use std::env;
+
+    // This logic is all tailored for MSVC, if we're not that then bail out
+    // early.
+    if !target.contains("msvc") {
+        return None;
+    }
+
+    // Looks like msbuild isn't located in the same location as other tools like
+    // cl.exe and lib.exe. To handle this we probe for it manually with
+    // dedicated registry keys.
+    if tool.contains("msbuild") {
+        return impl_::find_msbuild(target);
+    }
+
+    // If VCINSTALLDIR is set, then someone's probably already run vcvars and we
+    // should just find whatever that indicates.
+    if env::var_os("VCINSTALLDIR").is_some() {
+        return env::var_os("PATH")
+            .and_then(|path| env::split_paths(&path).map(|p| p.join(tool)).find(|p| p.exists()))
+            .map(|path| Tool::new(path.into()));
+    }
+
+    // Ok, if we're here, now comes the fun part of the probing. Default shells
+    // or shells like MSYS aren't really configured to execute `cl.exe` and the
+    // various compiler tools shipped as part of Visual Studio. Here we try to
+    // first find the relevant tool, then we also have to be sure to fill in
+    // environment variables like `LIB`, `INCLUDE`, and `PATH` to ensure that
+    // the tool is actually usable.
+
+    return impl_::find_msvc_15(tool, target)
+        .or_else(|| impl_::find_msvc_14(tool, target))
+        .or_else(|| impl_::find_msvc_12(tool, target))
+        .or_else(|| impl_::find_msvc_11(tool, target));
+}
+
+/// A version of Visual Studio
+pub enum VsVers {
+    /// Visual Studio 12 (2013)
+    Vs12,
+    /// Visual Studio 14 (2015)
+    Vs14,
+    /// Visual Studio 15 (2017)
+    Vs15,
+
+    /// Hidden variant that should not be matched on. Callers that want to
+    /// handle an enumeration of `VsVers` instances should always have a default
+    /// case meaning that it's a VS version they don't understand.
+    #[doc(hidden)]
+    __Nonexhaustive_do_not_match_this_or_your_code_will_break,
+}
+
+/// Find the most recent installed version of Visual Studio
+///
+/// This is used by the cmake crate to figure out the correct
+/// generator.
+#[cfg(not(windows))]
+pub fn find_vs_version() -> Result<VsVers, String> {
+    Err(format!("not windows"))
+}
+
+/// Documented above
+#[cfg(windows)]
+pub fn find_vs_version() -> Result<VsVers, String> {
+    use std::env;
+
+    match env::var("VisualStudioVersion") {
+        Ok(version) => {
+            match &version[..] {
+                "15.0" => Ok(VsVers::Vs15),
+                "14.0" => Ok(VsVers::Vs14),
+                "12.0" => Ok(VsVers::Vs12),
+                vers => Err(format!("\n\n\
+                                     unsupported or unknown VisualStudio version: {}\n\
+                                     if another version is installed consider running \
+                                     the appropriate vcvars script before building this \
+                                     crate\n\
+                                     ", vers)),
+            }
+        }
+        _ => {
+            // Check for the presense of a specific registry key
+            // that indicates visual studio is installed.
+            if impl_::has_msbuild_version("15.0") {
+                Ok(VsVers::Vs15)
+            } else if impl_::has_msbuild_version("14.0") {
+                Ok(VsVers::Vs14)
+            } else if impl_::has_msbuild_version("12.0") {
+                Ok(VsVers::Vs12)
+            } else {
+                Err(format!("\n\n\
+                             couldn't determine visual studio generator\n\
+                             if VisualStudio is installed, however, consider \
+                             running the appropriate vcvars script before building \
+                             this crate\n\
+                             "))
+            }
+        }
+    }
+}
+
+#[cfg(windows)]
+mod impl_ {
+    use std::env;
     use std::ffi::OsString;
     use std::mem;
     use std::path::{Path, PathBuf};
+    use std::fs::File;
+    use std::io::Read;
     use registry::{RegistryKey, LOCAL_MACHINE};
+    use com;
+    use setup_config::{SetupConfiguration, SetupInstance};
+
+    use Tool;
 
     struct MsvcTool {
         tool: PathBuf,
@@ -82,47 +192,91 @@ pub fn find_tool(target: &str, tool: &str) -> Option<Tool> {
         }
     }
 
-    // This logic is all tailored for MSVC, if we're not that then bail out
-    // early.
-    if !target.contains("msvc") {
-        return None;
-    }
+    // In MSVC 15 (2017) MS once again changed the scheme for locating
+    // the tooling.  Now we must go through some COM interfaces, which
+    // is super fun for Rust.
+    pub fn find_msvc_15(tool: &str, target: &str) -> Option<Tool> {
+        otry!(com::initialize().ok());
+
+        let config = otry!(SetupConfiguration::new().ok());
+        let iter = otry!(config.enum_all_instances().ok());
+        for instance in iter {
+            let instance = otry!(instance.ok());
+            let tool = tool_from_vs15_instance(tool, target, &instance);
+            if tool.is_some() {
+                return tool;
+            }
+        }
 
-    // Looks like msbuild isn't located in the same location as other tools like
-    // cl.exe and lib.exe. To handle this we probe for it manually with
-    // dedicated registry keys.
-    if tool.contains("msbuild") {
-        return find_msbuild(target);
+        None
     }
 
-    // If VCINSTALLDIR is set, then someone's probably already run vcvars and we
-    // should just find whatever that indicates.
-    if env::var_os("VCINSTALLDIR").is_some() {
-        return env::var_os("PATH")
-            .and_then(|path| env::split_paths(&path).map(|p| p.join(tool)).find(|p| p.exists()))
-            .map(|path| Tool::new(path.into()));
+    fn tool_from_vs15_instance(tool: &str, target: &str,
+                               instance: &SetupInstance) -> Option<Tool> {
+        let (bin_path, lib_path, include_path) = otry!(vs15_vc_paths(target, instance));
+        let tool_path = bin_path.join(tool);
+        if !tool_path.exists() { return None };
+
+        let mut tool = MsvcTool::new(tool_path);
+        tool.path.push(bin_path.clone());
+        tool.libs.push(lib_path);
+        tool.include.push(include_path);
+
+        if let Some((atl_lib_path, atl_include_path)) = atl_paths(target, &bin_path) {
+            tool.libs.push(atl_lib_path);
+            tool.include.push(atl_include_path);
+        }
+
+        otry!(add_sdks(&mut tool, target));
+
+        Some(tool.into_tool())
     }
 
-    // Ok, if we're here, now comes the fun part of the probing. Default shells
-    // or shells like MSYS aren't really configured to execute `cl.exe` and the
-    // various compiler tools shipped as part of Visual Studio. Here we try to
-    // first find the relevant tool, then we also have to be sure to fill in
-    // environment variables like `LIB`, `INCLUDE`, and `PATH` to ensure that
-    // the tool is actually usable.
+    fn vs15_vc_paths(target: &str, instance: &SetupInstance) -> Option<(PathBuf, PathBuf, PathBuf)> {
+        let instance_path: PathBuf = otry!(instance.installation_path().ok()).into();
+        let version_path = instance_path.join(r"VC\Auxiliary\Build\Microsoft.VCToolsVersion.default.txt");
+        let mut version_file = otry!(File::open(version_path).ok());
+        let mut version = String::new();
+        otry!(version_file.read_to_string(&mut version).ok());
+        let version = version.trim();
+        let host = match host_arch() {
+            X86 => "X86",
+            X86_64 => "X64",
+            _ => return None,
+        };
+        let target = otry!(lib_subdir(target));
+        let path = instance_path.join(r"VC\Tools\MSVC").join(version);
+        let bin_path = path.join("bin").join(&format!("Host{}", host)).join(&target);
+        let lib_path = path.join("lib").join(&target);
+        let include_path = path.join("include");
+        Some((bin_path, lib_path, include_path))
+    }
 
-    return find_msvc_latest(tool, target, "15.0")
-        .or_else(|| find_msvc_latest(tool, target, "14.0"))
-        .or_else(|| find_msvc_12(tool, target))
-        .or_else(|| find_msvc_11(tool, target));
+    fn atl_paths(target: &str, path: &Path) -> Option<(PathBuf, PathBuf)> {
+        let atl_path = path.join("atlfmc");
+        let sub = otry!(lib_subdir(target));
+        if atl_path.exists() {
+            Some((atl_path.join("lib").join(sub), atl_path.join("include")))
+        } else {
+            None
+        }
+    }
 
-    // For MSVC 14 or newer we need to find the Universal CRT as well as either
+    // For MSVC 14 we need to find the Universal CRT as well as either
     // the Windows 10 SDK or Windows 8.1 SDK.
-    fn find_msvc_latest(tool: &str, target: &str, ver: &str) -> Option<Tool> {
-        let vcdir = otry!(get_vc_dir(ver));
+    pub fn find_msvc_14(tool: &str, target: &str) -> Option<Tool> {
+        let vcdir = otry!(get_vc_dir("14.0"));
         let mut tool = otry!(get_tool(tool, &vcdir, target));
+        otry!(add_sdks(&mut tool, target));
+        Some(tool.into_tool())
+    }
+
+    fn add_sdks(tool: &mut MsvcTool, target: &str) -> Option<()> {
         let sub = otry!(lib_subdir(target));
         let (ucrt, ucrt_version) = otry!(get_ucrt_dir());
 
+        tool.path.push(ucrt.join("bin").join(&ucrt_version).join(sub));
+
         let ucrt_include = ucrt.join("include").join(&ucrt_version);
         tool.include.push(ucrt_include.join("ucrt"));
 
@@ -145,14 +299,13 @@ pub fn find_tool(target: &str, tool: &str) -> Option<Tool> {
             tool.include.push(sdk_include.join("um"));
             tool.include.push(sdk_include.join("winrt"));
             tool.include.push(sdk_include.join("shared"));
-        } else {
-            return None;
         }
-        Some(tool.into_tool())
+
+        Some(())
     }
 
     // For MSVC 12 we need to find the Windows 8.1 SDK.
-    fn find_msvc_12(tool: &str, target: &str) -> Option<Tool> {
+    pub fn find_msvc_12(tool: &str, target: &str) -> Option<Tool> {
         let vcdir = otry!(get_vc_dir("12.0"));
         let mut tool = otry!(get_tool(tool, &vcdir, target));
         let sub = otry!(lib_subdir(target));
@@ -168,7 +321,7 @@ pub fn find_tool(target: &str, tool: &str) -> Option<Tool> {
     }
 
     // For MSVC 11 we need to find the Windows 8 SDK.
-    fn find_msvc_11(tool: &str, target: &str) -> Option<Tool> {
+    pub fn find_msvc_11(tool: &str, target: &str) -> Option<Tool> {
         let vcdir = otry!(get_vc_dir("11.0"));
         let mut tool = otry!(get_tool(tool, &vcdir, target));
         let sub = otry!(lib_subdir(target));
@@ -403,8 +556,52 @@ pub fn find_tool(target: &str, tool: &str) -> Option<Tool> {
         max_key
     }
 
+    pub fn has_msbuild_version(version: &str) -> bool {
+        match version {
+            "15.0" => {
+                find_msbuild_vs15("x86_64-pc-windows-msvc").is_some() ||
+                    find_msbuild_vs15("i686-pc-windows-msvc").is_some()
+            }
+            "12.0" | "14.0" => {
+                LOCAL_MACHINE.open(
+                    &OsString::from(format!("SOFTWARE\\Microsoft\\MSBuild\\ToolsVersions\\{}",
+                                            version))).is_ok()
+            }
+            _ => false
+        }
+    }
+
     // see http://stackoverflow.com/questions/328017/path-to-msbuild
-    fn find_msbuild(target: &str) -> Option<Tool> {
+    pub fn find_msbuild(target: &str) -> Option<Tool> {
+        // VS 15 (2017) changed how to locate msbuild
+        if let Some(r) = find_msbuild_vs15(target) {
+            return Some(r);
+        } else {
+            find_old_msbuild(target)
+        }
+    }
+
+    fn find_msbuild_vs15(target: &str) -> Option<Tool> {
+        // Seems like this could also go through SetupConfiguration,
+        // or that find_msvc_15 could just use this registry key
+        // instead of the COM interface.
+        let key = r"SOFTWARE\WOW6432Node\Microsoft\VisualStudio\SxS\VS7";
+        LOCAL_MACHINE.open(key.as_ref())
+            .ok()
+            .and_then(|key| {
+                key.query_str("15.0").ok()
+            })
+            .map(|path| {
+                let path = PathBuf::from(path).join(r"MSBuild\15.0\Bin\MSBuild.exe");
+                let mut tool = Tool::new(path);
+                if target.contains("x86_64") {
+                    tool.env.push(("Platform".into(), "X64".into()));
+                }
+                tool
+            })
+    }
+
+    fn find_old_msbuild(target: &str) -> Option<Tool> {
         let key = r"SOFTWARE\Microsoft\MSBuild\ToolsVersions";
         LOCAL_MACHINE.open(key.as_ref())
             .ok()