dmstyle: Sign-compare warning fix.

dlls/dmstyle/dmutils.c

@@ -628,8 +628,9 @@ const char *debugstr_dmreturn (DWORD code) {
 /* generic flag-dumping function */
 const char* debugstr_flags (DWORD flags, const flag_info* names, size_t num_names){
 	static char buffer[128] = "", *ptr = &buffer[0];
-	unsigned int i, size = sizeof(buffer);
-		
+	unsigned int i;
+	int size = sizeof(buffer);
+
 	for (i=0; i < num_names; i++) {
 		if ((flags & names[i].val)) {
 			int cnt = snprintf(ptr, size, "%s ", names[i].name);