[PATCH] Resubmit "Improve Windows toolchain support for non-standard environments."

[Hans Wennborg]

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Comment at: lib/Driver/MSVCToolChain.cpp:218
@@ +217,3 @@
+// system (as reported by the registry).
+bool Windows::getVisualStudioBinariesFolder(const char *clangProgramPath,
+                                            std::string &path) const {
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The Windows toolchain was renamed to MSVCToolChain in r220362.

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Comment at: lib/Driver/MSVCToolChain.cpp:225
@@ +224,3 @@
+  // First check the environment variables that vsvars32.bat sets.
+  const char *vcinstalldir = getenv("VCINSTALLDIR");
+  if (vcinstalldir) {
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Should this use llvm::sys::Process::GetEnv like below?

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Comment at: lib/Driver/MSVCToolChain.cpp:228
@@ +227,3 @@
+    BinDir = vcinstalldir;
+    llvm::sys::path::append(BinDir, "VC");
+  } else {
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Should this append VC\bin ?

When I applied this patch, clang no longer finds link.exe in my VS2012 environment.

VCINSTALLDIR is set to C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\ and link.exe is at C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\bin\link.exe

If I unset VSINSTALLDIR it seems to work due to the PATH walking below.

http://reviews.llvm.org/D5892