[travis] build VPX support
[travis] build VPX support

kollix/qxmpp,cccco/qxmpp,LightZam/qxmpp,cccco/qxmpp,Kaffeine/qxmpp,LightZam/qxmpp,Kaffeine/qxmpp,gamenet/qxmpp,kollix/qxmpp,Ilyatk/qxmpp,pol51/QXMPP-CMake,pol51/QXMPP-CMake,pol51/QXMPP-CMake,KangLin/qxmpp,Kaffeine/qxmpp,cccco/qxmpp,olesalscheider/qxmpp,Ilyatk/qxmpp,KangLin/qxmpp,gamenet/qxmpp,ycsoft/qxmpp,olesalscheider/qxmpp,ycsoft/qxmpp,kollix/qxmpp,LightZam/qxmpp,olesalscheider/qxmpp,ycsoft/qxmpp,KangLin/qxmpp,Ilyatk/qxmpp,gamenet/qxmpp