Cleanup: fixed compiler warning about `strncat`

`strncat(command, "x", 1)` is the same as `strcat(command, "x")`, except
that the latter form doesn't trigger a GCC warning.

No functional changes.

extern/cuew/src/cuew.c

@@ -879,7 +879,7 @@ int cuewCompilerVersion(void) {
   }
 
   /* get --version output */
-  strncat(command, "\"", 1);
+  strcat(command, "\"");
   strncat(command, path, sizeof(command) - 1);
   strncat(command, "\" --version", sizeof(command) - strlen(path) - 1);
   pipe = popen(command, "r");