Fixed bug 1744 - DirectFB video and renderer API is not updated

tomaszewski.p

Recent changes in SDL_sysrenderer.h and SDL_sysvideo.h had no impact on directfb backend.

Attached patch:
- updates interface,
- resolves uninitialized variable reading,
- changes logging tio use SDL_Log API,
- updates configure to use DIRECTFBCONFIG variable instead direct call to directfb-config.

configure

@@ -20263,7 +20263,7 @@ fi
         else
             set -- `echo $DIRECTFB_REQUIRED_VERSION | sed 's/\./ /g'`
             NEED_VERSION=`expr $1 \* 10000 + $2 \* 100 + $3`
-            set -- `directfb-config --version | sed 's/\./ /g'`
+            set -- `$DIRECTFBCONFIG --version | sed 's/\./ /g'`
             HAVE_VERSION=`expr $1 \* 10000 + $2 \* 100 + $3`
             if test $HAVE_VERSION -ge $NEED_VERSION; then
                 DIRECTFB_CFLAGS=`$DIRECTFBCONFIG --cflags`