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.
wm4