Only check for a working C++ compiler if the avifile provider is going to be built.
Only check for a working C++ compiler if the avifile provider is going
to be built.

djbclark/directfb-core-DirectFB,Distrotech/DirectFB,DirectFB/directfb,jcdubois/DirectFB,mtsekm/test,kevleyski/directfb,deniskropp/DirectFB,djbclark/directfb-core-DirectFB,lancebaiyouview/DirectFB,DirectFB/directfb,mtsekm/test,lancebaiyouview/DirectFB,kaostao/directfb,kevleyski/DirectFB-1,kevleyski/directfb,djbclark/directfb-core-DirectFB,kevleyski/directfb,dfbdok/DirectFB1,deniskropp/DirectFB,lancebaiyouview/DirectFB,kaostao/directfb,kevleyski/directfb,lancebaiyouview/DirectFB,kaostao/directfb,sklnet/DirectFB,DirectFB/directfb,dfbdok/DirectFB1,sklnet/DirectFB,jcdubois/DirectFB,kevleyski/DirectFB-1,mtsekm/test,sklnet/DirectFB,Distrotech/DirectFB,dfbdok/DirectFB1,deniskropp/DirectFB,deniskropp/DirectFB,jcdubois/DirectFB,kevleyski/DirectFB-1,Distrotech/DirectFB,kevleyski/DirectFB-1,djbclark/directfb-core-DirectFB,sklnet/DirectFB