This should fix some issues, such as not being able to set the
"no-video" option with MPV_FORMAT_FLAG.
Note that this changes semantics a bit. Now setting an option strictly
overwrite it, even if the corresponding command line option does not.
For example, if we change --sub to append by default, then setting the
"sub" option via the client API would still never append. (Oddly, this
also applies to --vf-add, which will overwrite the old value when using
the client API.)
I'm doing this because there's no proper separation between the command
line parser and setting an option using the MPV_FORMAT_STRING format.
Maybe the solution to this mess would be adding format aware code (i.e.
m_option_set_node) to every option type, and falling back to strings
only if needed - but this would mean that you couldn't set e.g. an
integer option using MPV_FORMAT_STRING, which doesn't seem to be ideal
either.
In conclusion, the current approach seems to be most robust, but I'm
open to suggestions should someone find that these semantics are a
problem.
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.
Commit 2c2c1203 sorted the output of --list-options, but the same code
ias also used for listing sub-options, such as --vo=scale:help. For sub-
options, the order actually matters.
Until now, --list-options printed options in random order. There
literally wasn't any logic in its order, they just appeared as they were
declared. So just sort them.
Note that we can't sort them in advance, because for certain things
internal to m_config, the order actually matters.
Also we're using strcasecmp(), which is bad (locale dependent), but this
is output intended for human consumption, so it's not a problem.
This is only half-implemented: actually the option will first be
converted from mpv_node to its native type, then it's converted to a
string, and then back to its native type. This is because the option
API was made for strings and not anything else.
Other than being grossly inelegant, the only downside is probably with
string lists and key/value lists, which don't escape strings containing
syntax elements correctly.
Always pass around mp_log contexts in the option parser code. This of
course affects all users of this API as well.
In stream.c, pass a mp_null_log, because we can't do it properly yet.
This will be fixed later.
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.
