saves some bytes of memory and removes the limit on the maximum number of vhosts and location blocks.

while there, add capsicum for the logger process

use imsg to handle ALL kinds of IPC in gmid. This simplifies and shorten the code, and makes everything more uniform too.

log.o is linked to some regress/ stuff. Calling from there a vhost_* function means that we should link the regress/stuff to server.o too (and that would pull in other stuff...). Moving the call is easier, and also probably better.

Include gmid.h as first header in every file, as it then includes config.h (that defines _GNU_SOURCE for instance). Fix also a warning about unsigned vs signed const char pointers in openssl.

accept4(2) isn't part of any standard (even though it'll be part in the future) and raises warnings on some linux distro. Moreover, we don't have thread that may fork at any time, so doing a mark_nonblock after isn't a big deal.