Wrap #pragma clang in #if __clang__, else VS produces fatal warnings.

indra/test/lltut.h

@@ -75,10 +75,14 @@ namespace tut
 // overloads declared above.
 
 // turn off warnings about unused functions from clang for tut package
+#if __clang__
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wunused-function"
+#endif
 #include <tut/tut.hpp>
+#if __clang__
 #pragma clang diagnostic pop
+#endif
 
 // The functions BELOW this point actually consume tut.hpp functionality.
 namespace tut