All authors of the current code have agreed (as far as this commit
requires).
options.c/options.h will take more effort, because it contains all the
option declarations, and thus is touched extremely often.
m_option.c is technically still GPL, because of commit 2c82d5a1d8
(michael has agreed to LGPL, but only once the core of mpv is LGPL).
The geometry parsing code in m_option.c was originally by someone who
could not be reached. However, it was heavily rewritten anyway, and only
the syntax remains (i.e. not copyright-relevant).
parse_commandline.c contains a change by "adland" (commit 1d0ac71ae8),
who could not be reached - this this specific part is GPL only.
Fortunately, it matters only for DVD (and even then is more like a hack,
but whatever).
There are some other relevant changes, but they have all been reverted,
moved somewhere else, deleted, or replaced.
Often, user configs set options that are not suitable for encoding.
Usually, playback and encoding are pretty different things, so it makes
sense to keep them strictly separate. There are several possible
solutions. The approach taken by this commit is to basically ignore the
default config settings, and switch to an [encoding] config profile
section instead. This also makes it impossible to have --o in a config
file, because --o enables encode mode.
See github issue #727 for discussion.
Since m_option.h and options.h are extremely often included, a lot of
files have to be changed.
Moving path.c/h to options/ is a bit questionable, but since this is
mainly about access to config files (which are also handled in
options/), it's probably ok.