Fix compatibility with the msvc AI compiler option

[rnk]

Summary

The unsupported /AI option accepts directory paths in a manner similar to the supported /I option and allows spaces between the flag and the directory. An example snippet from our production compile that broke on clang-cl.exe because it read the path as an input file.

/AI %WindowsSdkDir%\References\%WindowsSDKVersion% /I %WindowsSdkDir%\Include\%WindowsSDKVersion%\winrt

[rnk]

lgtm, I'll go ahead and commit this soon.

[rnk]

• add test

cfe/trunk/include/clang/Driver/CLCompatOptions.td

 def _SLASH_Zc_wchar_t : CLIgnoredFlag<"Zc:wchar_t">;
 def _SLASH_Zm : CLIgnoredJoined<"Zm">;
 def _SLASH_Zo : CLIgnoredFlag<"Zo">;
 def _SLASH_Zo_ : CLIgnoredFlag<"Zo-">;
 
 
 // Unsupported:
 
-def _SLASH_AI : CLJoined<"AI">;
+def _SLASH_AI : CLJoinedOrSeparate<"AI">;
 def _SLASH_Bt : CLFlag<"Bt">;
 def _SLASH_Bt_plus : CLFlag<"Bt+">;
 def _SLASH_clr : CLJoined<"clr">;
 def _SLASH_doc : CLJoined<"doc">;
 def _SLASH_FA_joined : CLJoined<"FA">;
 def _SLASH_favor : CLJoined<"favor">;
 def _SLASH_F : CLFlag<"F">;
 def _SLASH_Fm : CLJoined<"Fm">;

cfe/trunk/test/Driver/cl-options.c

 // Support ignoring warnings about unused arguments.
 // RUN: %clang_cl /Abracadabra -Qunused-arguments -### -- %s 2>&1 | FileCheck -check-prefix=UNUSED %s
 // UNUSED-NOT: argument unused during compilation
 
 // Unsupported but parsed options. Check that we don't error on them.
 // (/Zs is for syntax-only)
 // RUN: %clang_cl /Zs \
 // RUN:     /AIfoo \
+// RUN:     /AI foo_does_not_exist \
 // RUN:     /Bt \
 // RUN:     /Bt+ \
 // RUN:     /clr:pure \
 // RUN:     /docname \
 // RUN:     /EHsc \
 // RUN:     /F \
 // RUN:     /FA \
 // RUN:     /FAc \