Use the existing definition of __func__

Now that library is in the include path when compiling metatest.c, don't
duplicate the definition of __func__ from library/common.h.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/programs/test/metatest.c b/programs/test/metatest.c
index 1724aed..392b638 100644
--- a/programs/test/metatest.c
+++ b/programs/test/metatest.c
@@ -34,6 +34,7 @@
 #include "test/helpers.h"
 #include "test/macros.h"
 #include "test/memory.h"
+#include "common.h"
 
 #include <stdio.h>
 #include <string.h>
@@ -42,11 +43,6 @@
 #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.