Prepare for a Decoder API redesign based on an abstract class with
virtual methods.

Using libopus and libogg.

Allow the function to be cancelled.

Fixes potential access to uninitialised memory.

After we've been hit by Large File Support problems several times in
the past week (which only occur on 32 bit platforms, which I don't
have), this is yet another attempt to fix the issue.

This updates the copyright header to all be the same, which is
pretty much an update of where to mail request for a copy of the GPL
and the years of the MPD project. This also puts all committers under
'The Music Player Project' umbrella. These entries should go
individually in the AUTHORS file, for consistancy.

The try_decode() method may have read some data from the stream, which
is now lost.  To make this data available to other methods, get it
back by rewinding the input stream after each try_decode() invocation.

The ogg and wavpack plugins did this manually and inconsistently; this
code can now be removed.

The source _ogg_common.c does not need any symbols from
_flac_common.h, but including it leads to compiler errors when libflac
isn't available.

Renamed all functions and variables.

Everybody should use struct input_stream.

These plugins are not input plugins, they are decoder plugins.  No
CamelCase in the directory name.

Don't compile the sources of disabled decoder plugins at all, and
don't attempt to register these.

On our way to stabilize the decoder API, we will one day remove the
input stream functions.  The most basic function, read() will be
provided by decoder_api.h with this patch.  It already contains a loop
(still with manual polling), error/eof handling and decoder command
checks.  This kind of code used to be duplicated in all decoder
plugins.

InputPlugin is the API which is implemented by a decoder plugin.  This
belongs to the public API/ABI, so move it to decoder_api.h.  It will
later be renamed to something like "decoder_plugin".

Include only headers which are really required.  This speeds up
compilation and helps detect cross-layer accesses.

If nothing has been read from the input stream, we don't have to
rewind it.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7397 09075e82-0dd4-0310-85a5-a0d7c8717e4f

The variable "to_read" is never modified except in the last iteration
of the while loop.  This means the while condition will never become
false, as the body will break before that may be checked.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7396 09075e82-0dd4-0310-85a5-a0d7c8717e4f

This will make refactoring features easier, especially now that
pthreads support and larger refactorings are on the horizon.

Hopefully, this will make porting to other platforms (even
non-UNIX-like ones for masochists) easier, too.

os_compat.h will house all the #includes for system headers
considered to be the "core" of MPD.  Headers for optional
features will be left to individual source files.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7130 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@7109 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@7108 09075e82-0dd4-0310-85a5-a0d7c8717e4f

ogg_stream_type_detect may not be compiled correctly
when compiling FLAC (1.1.4+) without Vorbis

git-svn-id: https://svn.musicpd.org/mpd/trunk@6896 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@5834 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@4660 09075e82-0dd4-0310-85a5-a0d7c8717e4f