Revert r167567, restoring the ability of clang to run gcc in cases where it
can't handle the input file type. This resulted in PR14338.

llvm-svn: 168024
diff --git a/clang/lib/Driver/WindowsToolChain.cpp b/clang/lib/Driver/WindowsToolChain.cpp
index a93702e..ac65187 100644
--- a/clang/lib/Driver/WindowsToolChain.cpp
+++ b/clang/lib/Driver/WindowsToolChain.cpp
@@ -37,7 +37,12 @@
 
 Tool &Windows::SelectTool(const Compilation &C, const JobAction &JA,
                           const ActionList &Inputs) const {
-  Action::ActionClass Key = JA.getKind();
+  Action::ActionClass Key;
+  if (getDriver().ShouldUseClangCompiler(C, JA, getTriple()))
+    Key = Action::AnalyzeJobClass;
+  else
+    Key = JA.getKind();
+
   bool UseIntegratedAs = C.getArgs().hasFlag(options::OPT_integrated_as,
                                              options::OPT_no_integrated_as,
                                              IsIntegratedAssemblerDefault());