New video output driver: "vmem", for direct memory access.

Sometimes our list of video output modules is still not enough for an
external libvlc application with specific requirements. For instance, an
SDL application running in full screen cannot open a new window on Linux
(this is a known libSDL limitation). This vmem video output allows it to
asynchronously render the video into an SDL_Surface, with full locking.

Resolution or pitch changes are not supported yet. I'd advise against
them however, since they often require a full chroma unload/reload
operation, which is quite expensive.

I also believe this feature should be directly integrated into libvlc,
but I don't want to be too intrusive yet.

configure.ac

@@ -1205,7 +1205,7 @@ VLC_ADD_PLUGINS([converter_fixed mono])
 VLC_ADD_PLUGINS([trivial_resampler ugly_resampler])
 VLC_ADD_PLUGINS([trivial_channel_mixer trivial_mixer])
 VLC_ADD_PLUGINS([playlist export nsc xtag])
-VLC_ADD_PLUGINS([i420_rgb grey_yuv rawvideo blend scale image logo magnify puzzle colorthres])
+VLC_ADD_PLUGINS([i420_rgb grey_yuv rawvideo blend scale image vmem logo magnify puzzle colorthres])
 VLC_ADD_PLUGINS([wav araw subtitle vobsub adpcm a52sys dtssys au ty voc xa nuv smf])
 VLC_ADD_PLUGINS([access_directory access_file access_udp access_tcp])
 VLC_ADD_PLUGINS([access_http access_mms access_ftp access_rtmp])

modules/video_output/Modules.am

@@ -17,3 +17,5 @@ SOURCES_opengl = opengl.c
 SOURCES_opengllayer = opengllayer.m
 SOURCES_image = image.c
 SOURCES_directfb = directfb.c
+SOURCES_vmem = vmem.c
+