I've run nm on the GStreamer framework (1.2.x) and it appears to include the use of NSGetEnviron():

GStreamer(libglib-2_0_a_armv7_-libglib_2_0_la-genviron.o) (for
architecture armv7):
U __NSGetEnviron

for the arm architecture in glib's genviron.  This is true of the prebuilt libraries and building via cerbero.  Unfortunately this call will cause a private API use rejection upon submitting an iOS app to Apple.  NSGetEnviron() is an OS X thing that's not supported on iOS to the best of my knowledge (at least officially).

The issue appears to lie in cerbero/sources/ios_universal/armv7/glib-2.38.0/glib/genviron.c:

#ifdef HAVE__NSGETENVIRON
#define environ (*_NSGetEnviron())
#else
/* According to the Single Unix Specification, environ is not
* in any system header, although unistd.h often declares it.
*/
extern char **environ;
#endif

I don't know whether HAVE__NSGETENVIRON should be defined differently somewhere for iOS arm builds or the file should be patched such that it calls a dummy function?