libevent2 can still somehowe call client_read even in code paths that never enable reading from the evbuffer. Can't reproduce on the libevent in base on OpenBSD. It's a bit ugly, but it's a small workaround for something that otherwise *always* make gmid crash when linked against libevent2. (client_read works under the assumption that c->host != NULL, matched_proxy crashes otherwise.)

forgot to rename variable in lib.sh: dont_check -> dont_check_server_alive.

while there also kill an unused rule `regress', it's now redundant since all the tests are run together.

while there also change the dependency in the makefile: iri_test should be alone, not as deps of `data'.