apparently msvc defines _STDCALL_SUPPORTED, so we should
too.  Patch by Per Linden!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@111236 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 1e8ed79..77319e1 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -1350,6 +1350,7 @@
     // We lost the original triple, so we use the default.
     Builder.defineMacro("_M_IX86", "600");
     Builder.defineMacro("_INTEGRAL_MAX_BITS", "64");
+    Builder.defineMacro("_STDCALL_SUPPORTED");
   }
 };
 } // end anonymous namespace