[PATCH] D13692: Silence warning for unrecognised "-std=c99" warning on MSVC

[Saleem Abdulrasool via llvm-commits]

compnerd added inline comments.

================
Comment at: lib/builtins/CMakeLists.txt:369
@@ +368,3 @@
+        set(_cflags "-std=c99")
+      endif ()
+
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How about making this more similar to the other flags checks?  We could then just do the append_if


http://reviews.llvm.org/D13692