I suggest adding a comment above `close()` - the git text is pretty good, here's an alternate condensed suggestion:
```c
    /* Call close() on the socket before calling mysql_close(). This
     * prevents mysql_close() from calling shutdown() on the socket.
     * The difference is that close() acts on the current process only,
     * while shutdown() acts for all parent and child processes, which
     * has impacts on applications using a forked worker strategy.
     */
```