apple: Patched to compile with older (mac 10.7) SDKs (thanks, Ken and Ryan!).

src/physfs_platform_apple.m

@@ -50,7 +50,7 @@ char *__PHYSFS_platformCalcPrefDir(const char *org, const char *app)
     {
         NSArray *paths = NSSearchPathForDirectoriesInDomains(NSApplicationSupportDirectory, NSUserDomainMask, TRUE);
         BAIL_IF(!paths, PHYSFS_ERR_OS_ERROR, NULL);
-        NSString *path = (NSString *) paths[0];
+        NSString *path = (NSString *) [paths objectAtIndex:0];
         BAIL_IF(!path, PHYSFS_ERR_OS_ERROR, NULL);
         size_t len = [path lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
         const size_t applen = strlen(app);