[cl-compat] Change /JMC from unsupported to ignored.

[zturner]

Summary

This command line option doesn't really affect generated code, only generated debug info, and it's set by default in newer versions of VS, so it's annoying to have to turn it off in order to be able to use the VS Integration extension.

[rnk]

lgtm Can you file a bug about implementing /JMC and link it from the commit message?

[hans]

Thanks for fixing! Please also update the test in test/Driver/cl-options.c and include me on clang-cl code reviews.

clang/include/clang/Driver/CLCompatOptions.td

 def _SLASH_bigobj : CLIgnoredFlag<"bigobj">;
 def _SLASH_cgthreads : CLIgnoredJoined<"cgthreads">;
 def _SLASH_d2FastFail : CLIgnoredFlag<"d2FastFail">;
 def _SLASH_d2Zi_PLUS : CLIgnoredFlag<"d2Zi+">;
 def _SLASH_errorReport : CLIgnoredJoined<"errorReport">;
 def _SLASH_FC : CLIgnoredFlag<"FC">;
 def _SLASH_Fd : CLIgnoredJoined<"Fd">;
 def _SLASH_FS : CLIgnoredFlag<"FS">;
+def _SLASH_JMC : CLIgnoredFlag<"JMC">;
 def _SLASH_kernel_ : CLIgnoredFlag<"kernel-">;
 def _SLASH_nologo : CLIgnoredFlag<"nologo">;
 def _SLASH_openmp_ : CLIgnoredFlag<"openmp-">;
 def _SLASH_permissive_ : CLIgnoredFlag<"permissive-">;
 def _SLASH_RTC : CLIgnoredJoined<"RTC">;
 def _SLASH_sdl : CLIgnoredFlag<"sdl">;
 def _SLASH_sdl_ : CLIgnoredFlag<"sdl-">;
 def _SLASH_utf8 : CLIgnoredFlag<"utf-8">,

 def _SLASH_GL_ : CLFlag<"GL-">;
 def _SLASH_Gm : CLFlag<"Gm">;
 def _SLASH_Gm_ : CLFlag<"Gm-">;
 def _SLASH_GT : CLFlag<"GT">;
 def _SLASH_GZ : CLFlag<"GZ">;
 def _SLASH_H : CLFlag<"H">;
 def _SLASH_homeparams : CLFlag<"homeparams">;
 def _SLASH_hotpatch : CLFlag<"hotpatch">;
-def _SLASH_JMC : CLFlag<"JMC">;
 def _SLASH_kernel : CLFlag<"kernel">;
 def _SLASH_LN : CLFlag<"LN">;
 def _SLASH_MP : CLJoined<"MP">;
 def _SLASH_openmp : CLFlag<"openmp">;
 def _SLASH_Qfast_transcendentals : CLFlag<"Qfast_transcendentals">;
 def _SLASH_QIfist : CLFlag<"QIfist">;
 def _SLASH_Qimprecise_fwaits : CLFlag<"Qimprecise_fwaits">;
 def _SLASH_Qpar : CLFlag<"Qpar">;