pidgin/pidgin

Move PurpleProtocolMediaInterface to its own file.

2020-08-27, Gary Kramlich
96fc115d6c36
Move PurpleProtocolMediaInterface to its own file.

Also cleaned up a few minor things along the way.

Testing Done:
Compile, docs, didn't update the pot file, but did a voice call between pidgin2 and pidgin3.

Reviewed at https://reviews.imfreedom.org/r/90/
NULLSOURCES = [
'nullprpl.h',
'nullprpl.c'
]
# nullprpl isn't built by default; when it is built, it's dynamically linked
if DYNAMIC_NULL
null_prpl = shared_library('null', NULLSOURCES,
dependencies : [libpurple_dep, glib],
install : false, install_dir : PURPLE_PLUGINDIR)
endif