I booted ubuntu 16 and it has gcc 5.4. This patch worked just fine.

Please let me know if check_cxx11_for_libdpx.diff is no longer needed ??? and if I should check in the above.

I checked new patch (from my memory) on Slackware and it worked. So yeah, I think this check in configure.ac is not needed anymore.

Thank you -- I will check in the patch for cinelerra/Makefile soon.

So this means that the following additional line in "check_cxx11_for_libdpx.diff" as shown below is not needed either? It does not seem to match anything else and I have not tested it.

well, this is for my Slackware/i686 system where libva installed into non-standard location

if you prefer you can just add this line as separare commit (even in unlikely case pkg-config returned nothing you still have original -lva.. error shows up quite lately during configuration of internal ffmpeg, if vaapi was enabled (default))

@@ -1044,6 +1049,7 @@ FFMPEG_EXTRA_LDFLAGS=""
if test "x$WANT_VAAPI" != "xno" -a "x$HAVE_VAAPI" = "xyes"; then
FFMPEG_EXTRA_LDFLAGS+=' -lva'
EXTRA_LIBS+=' -lva'
+ EXTRA_LIBS+=' `pkg-config --libs libva`'
WANT_VAAPI="yes"
if test "x$HAVE_vaapi_x11" = "xyes"; then