make: fix GCC warnings

@@ -109,11 +109,11 @@
                         return 0; /* success */
                 }
                 UNBLOCK_INTERUPTS;
 
                 if (errno != EEXIST) {
-                        file_lock_error(msg, name, NOCATGETS("symlink(%s, %s)"),
+                        file_lock_error(msg, name, (char *)NOCATGETS("symlink(%s, %s)"),
                             (int) name, (int) lockname);
                         fprintf(stderr, "%s", msg);
                         return errno;
                 }