Turn off MSVC anti-portability propaganda in test program.

test/test_physfs.c

@@ -6,6 +6,8 @@
  *  This file written by Ryan C. Gordon.
  */
 
+#define _CRT_SECURE_NO_WARNINGS 1
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <errno.h>