[PATCH] clang-cl: Make /Za disable oldnames.lib dependency

[Charles Davis]

  This flag should be doing more stuff. This flag is supposed to request strict ANSI conformance (according to Microsoft's, uh... "unique" interpretation of that). That means at least (in GCC terms) `-fno-ms-extensions`, in addition to not auto-linking `OLDNAMES.LIB`. (The `/Ze` flag undoes the effects of `/Za`.)

  I seem to recall someone from MS on `cfe-dev` (and yes, they do exist!) saying that `/Za` is broken and shouldn't be used (cf. "/Za considered harmful" or some such). Are you sure you want to implement it, given that?

http://llvm-reviews.chandlerc.com/D1320