Merge branch 'jt/itimer-autoconf'

setitmer(2) and related API elements can be configured from
Makefile but autoconf did not know about it.

* jt/itimer-autoconf:
autoconf: check for setitimer()
autoconf: check for struct itimerval
git-compat-util.h: add missing semicolon after struct itimerval

diff --cc git-compat-util.h
Simple merge