zip: strip binary
openssl: strip binary
rtmpdump: do not install binaries
fontconfig: do not install binaries
windowmanager: do not enable 'windowmanager.service' by default

this is useless with xbmc in fullscreen/standalone mode, as
xbmc window won't even appear in  managed clients list. also
it could cause issues like xbmc losing focus.

3rdparty addons that need windowmanager for fullscreen/alt-tab/etc
can start it via 'systemctl start windowmanager.service'

closes #2675