Added macros to VISCHint.h to support both c and c++

llvm/include/llvm/SupportVISC/VISCHint.h

@@ -11,8 +11,9 @@
 #define VISC_HINT_HEADER
 
 /************************** Hint Routines ***************************/
-
+#ifdef __cplusplus
 namespace visc {
+#endif
 
   enum Target {
     None,
@@ -22,6 +23,7 @@ namespace visc {
     NUM_TARGETS
   };
 
+#ifdef __cplusplus
 }
-
+#endif
 #endif //VISC_RT_HEADER