Disable vdpau support if the detected libvdpau does not support MPEG-4.

Originally committed as revision 20854 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -2481,6 +2481,11 @@ check_func XOpenDisplay -lX11           &&
 check_func XShmCreateImage -lX11 -lXext &&
 check_func XFixesGetCursorImage -lX11 -lXext -lXfixes
 
+check_cpp_condition \
+    vdpau/vdpau.h "defined VDP_DECODER_PROFILE_MPEG4_PART2_ASP" ||
+    ( echolog "Please upgrade to libvdpau >= 0.2 if you would like vdpau support." &&
+      disable vdpau )
+
 enabled debug && add_cflags -g"$debuglevel" && add_asflags -g"$debuglevel"
 
 # add some useful compiler flags if supported