PL_ErrorDialog: fix clang warning about format string not a literal

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@1450 af15c1b1-3010-417e-b628-4374ebc0bcbd

Quake/pl_osx.m

@@ -72,6 +72,6 @@ void PL_ErrorDialog(const char *errorMsg)
 #else
     NSString* msg = [NSString stringWithCString:errorMsg encoding:NSASCIIStringEncoding];
 #endif
-    NSRunCriticalAlertPanel (@"Quake Error", msg, @"OK", nil, nil);
+    NSRunCriticalAlertPanel (@"Quake Error", @"%@", @"OK", nil, nil, msg);
 }