clang-cl: Support /showIncludes

This option prints information about #included files to stderr. Clang could
already do it, this patch just teaches the existing code about the /showIncludes
style and adds the flag.

Differential Revision: http://llvm-reviews.chandlerc.com/D1333

llvm-svn: 188037

clang/lib/Frontend/CompilerInvocation.cpp

@@ -518,6 +518,7 @@ static void ParseDependencyOutputArgs(DependencyOutputOptions &Opts,
   Opts.ShowHeaderIncludes = Args.hasArg(OPT_H);
   Opts.HeaderIncludeOutputFile = Args.getLastArgValue(OPT_header_include_file);
   Opts.AddMissingHeaderDeps = Args.hasArg(OPT_MG);
+  Opts.PrintShowIncludes = Args.hasArg(OPT_show_includes);
   Opts.DOTOutputFile = Args.getLastArgValue(OPT_dependency_dot);
 }