Unbreak VC++ build.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31464 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/System/Win32/Path.inc b/lib/System/Win32/Path.inc
index 048bf60..1eee2bb 100644
--- a/lib/System/Win32/Path.inc
+++ b/lib/System/Win32/Path.inc
@@ -124,7 +124,12 @@
 
   // Append a subdirectory passed on our process id so multiple LLVMs don't
   // step on each other's toes.
+#ifdef __MINGW32__
+  // Mingw's Win32 header files are broken.
   sprintf(pathname, "LLVM_%u", unsigned(GetCurrentProcessId()));
+#else
+  sprintf(pathname, "LLVM_%u", GetCurrentProcessId());
+#endif
   result.appendComponent(pathname);
 
   // If there's a directory left over from a previous LLVM execution that