fix for mingw64

* util.c: define MINGW_HAS_SECURE_API for qsort_s on recent
  mingw64.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57763 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

util.c

@@ -9,6 +9,10 @@
 
 **********************************************************************/
 
+#if defined __MINGW32__ || defined __MINGW64__
+#define MINGW_HAS_SECURE_API 1
+#endif
+
 #include "internal.h"
 
 #include <ctype.h>