Added some notes about --enable-multi, --enable-debug and --enable-trace.
Added some notes about --enable-multi, --enable-debug and --enable-trace.

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