build: Fix make distcheck.
build: Fix make distcheck.

Add CoreDFB_CallMode.h to the list of header files.

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