Attempt to fix BuildBot breakage with MSVC.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76722 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/Support/DataTypes.h.cmake b/include/llvm/Support/DataTypes.h.cmake
index 4d6fcc8..dddc1d1 100644
--- a/include/llvm/Support/DataTypes.h.cmake
+++ b/include/llvm/Support/DataTypes.h.cmake
@@ -95,6 +95,11 @@
 #include <stdlib.h>
 #include <stddef.h>
 #include <sys/types.h>
+#ifdef __cplusplus
+#include <cmath>
+#else
+#include <math.h>
+#endif
 typedef __int64 int64_t;
 typedef unsigned __int64 uint64_t;
 typedef signed int int32_t;