See attached build log.
(Please do not complain about the need for looking at the build log until you can provide an easy way to open bugs with the correct data picked out of a tinderbox log. Thanks.)
Created attachment 242401 [details]
Blerg, scons. Turns out it was not respecting CFLAGS or CC either.
Fixed all 3 env foibles in revbump rox-media-0.0.3-r1