[libmicrohttpd] Consider allowing SO_REUSEPORT when requested

[Milan Straka]

Hi all,

would you consider adding flag enabling SO_REUSEPORT on the listening
socket? Something like MHD_OPTION_SO_REUSEPORT? A compilation option
would probably have to be used to enable it.

I understand I can open the listening socket myself and pass it using
MHD_OPTION_LISTEN_SOCKET, but I think a HTTP server should allow using
SO_REUSEPORT nowadays.

Cheers,
Milan Straka