Update for recent changes to common submodule
Update for recent changes to common submodule

This just replaces every "$ERROR_CFLAGS" usage with a usage of
"$WARNING_CFLAGS $ERROR_CFLAGS" to get the same functionality as
previously.

Actually using that separation will happen later.

ystreet/gst-plugins-gl,ystreet/gst-plugins-gl,mapmapteam/gst-plugins-gl,ystreet/gst-plugins-gl,mapmapteam/gst-plugins-gl,mapmapteam/gst-plugins-gl