Index: lib/Driver/MinGWToolChain.cpp
===================================================================
--- lib/Driver/MinGWToolChain.cpp
+++ lib/Driver/MinGWToolChain.cpp
@@ -208,6 +208,7 @@
   if (DriverArgs.hasArg(options::OPT_nostdlibinc))
     return;
 
+#ifndef LLVM_ON_WIN32
   if (GetRuntimeLibType(DriverArgs) == ToolChain::RLT_Libgcc) {
     llvm::SmallString<1024> IncludeDir(GccLibDir);
     llvm::sys::path::append(IncludeDir, "include");
@@ -218,6 +219,7 @@
                      Base + Arch + "/sys-root/mingw/include");
     addSystemInclude(DriverArgs, CC1Args, IncludeDir.c_str());
   }
+#endif
   addSystemInclude(DriverArgs, CC1Args,
                    Base + Arch + llvm::sys::path::get_separator() + "include");
   addSystemInclude(DriverArgs, CC1Args, Base + "include");