avoid __dead and return at the end of main

reject non-gemini protocols with 53

s/uri/iri since we accept IRIs

fix build

fix remote_user for CGI and add -6 flag to enable ipv6

accept both ipv4 and ipv6

log also the port of the client

make FATAL and LOG inline functions other functions that aren't macros anymore. LOG went under a rename to logs because log is a builtin (the math function), or so gcc says.

macro reordering and while there replace SAFE_SETENV with an inline function. LOG is more difficult to transform into an inline function, given the string concatenations it does. The other LOG* and FATAL macros are fine as they already are.

simplify loop todo was initially there for an optimization: don't loop to MAX_USERS when you know the upper limit is todo.

simplify unveil/pledge calls

rename cgi_setpoll_on_* to cgi_poll_on_*

initialize error string to avoid returning garbage

ignore also SIGHUP SIGHUP is sent when the tty is detached and by default kills the process. When we run in the background we don't care anymore about the tty, so it should be safe for us to ignore SIGHUP. (frankly, I expected daemon(3) to do stuff like this for us).

fix CGI with new IRI parser With new IRI, parser the old assumption of path starting with ./ is no longer valid.