split out some functions from Open()
move static functions
sout_stream_id_t -> define struct as empty and use the pointer to store sout_input_t

functional change:
do not force asfh mux if user specified another one but only warn him (like for upd/ts)

makes data smaller:
 no need to store pointers to each item of the array

char *x[] = { "a", "b", "c" };
memory looks like => "a" "b" "c" (&x) &a &b &c

char x[][2] = { "a", "b", "c" };
memory looks like => (&x) "a" "b" "c"

macosx: move VLCFSPanel from VLCControls to VLCMainWindow since its the only class which should know about it

Close #5167

Some X servers cannot borrow VLC user privileges to attach to its
shared memory segments. This fallback should fix MIT-SHM with those
X servers. However other users will be able to snoop on the decoded
video frames.

The SDL audio output is gone. The SDL video output is not very useful
and it won't quite work with most SDL video plugins disabled.

SDL is mainly a dependency for SDL_image.

As things stand, we have a format that is neither S/PDIF nor linear,
so change the macros to remove the confusion.

This plugin modifies the output format. It caused a busy loop
and broke libmad on fixed-point architectures (fixes #5151).