fix detection on non-openbsd systems

look for libevent

keep original CFLAGS

define MANDIR

add compat for setproctitle This adds a check for setproctitle and for the (linux) prctl PR_SET_NAME. If setproctitle is not available, on linux we provide an implementation that use prctl (taken from tmux compat layer.)

let LEX and YACC be customizable via args

adjust CFLAGS detection

gen compat for getprogname

rework the configless mode: change flags and generate certs

fixing compat compilation include headers if needed and include config.h

missing ; in prototype

add missing getprogname test + eventually include err.h

more OpenBSD goodies

simplify CFLAGS/LDFLAGS autodetection