diff --git a/test/tconfig.c b/test/tconfig.c
index 256fed4df6..077c472d42 100644
--- a/test/tconfig.c
+++ b/test/tconfig.c
@@ -107,9 +107,15 @@ test_config_ctypes(void)
     vrfy_ctype(double, SIZEOF_DOUBLE);
 
     /* non-standard basic types */
+#ifdef HAVE___int64
+#if SIZEOF___INT64 >0
+    vrfy_ctype(__int64,SIZEOF___INT64);
+#endif
+#else
 #if SIZEOF_LONG_LONG > 0
     vrfy_ctype(long long, SIZEOF_LONG_LONG);
 #endif
+#endif
 
 #if SIZEOF_LONG_DOUBLE > 0
     vrfy_ctype(long double, SIZEOF_LONG_DOUBLE);