Fix MSVC build failure

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/programs/test/metatest.c b/programs/test/metatest.c
index a3d9d40..6a3e7a9 100644
--- a/programs/test/metatest.c
+++ b/programs/test/metatest.c
@@ -41,6 +41,11 @@
 #include <mbedtls/threading.h>
 #endif
 
+/* C99 feature missing from older versions of MSVC */
+#if (defined(_MSC_VER) && (_MSC_VER <= 1900))
+#define /*no-check-names*/ __func__ __FUNCTION__
+#endif
+
 
 /* This is an external variable, so the compiler doesn't know that we're never
  * changing its value.