Fixed bug #67635 php links to systemd libraries without using pkg-config

Patch from pacho at gentoo dot org

Rely on pkg-config for systemd >= 209
Failback on old check
improve previous, add message during configure
NEWS
Merge branch 'PHP-5.5' into PHP-5.6

* PHP-5.5:
  NEWS
  improve previous, add message during configure
  Fixed bug #67635 php links to systemd libraries without using pkg-config
NEWS