Commit Briefs
don't save the directory fd in c->pfd
scandir_fd already calls closedir, which in turns closes the fd
list instead of fixed-size array for vhosts and locations
saves some bytes of memory and removes the limit on the maximum number of vhosts and location blocks.
move all sandbox-related code to sandbox.c
while there, add capsicum for the logger process
refactoring: imsg everywhere
use imsg to handle ALL kinds of IPC in gmid. This simplifies and shorten the code, and makes everything more uniform too.
move vhost_should_log call to server.c
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.
fix various compilation errors
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.