The two functions clearStoredPlaylist() and addToStoredPlaylist()
don't belong into playlist.c.  clearStoredPlaylist() was a wrapper for
spl_clear(), and is converted into a CPP macro for now.

Renamed all public functions, prefix is "spl_".

No CamelCase in file names.

The list of commands is known at compile time.  Instead of creating a
linked list on startup, we can just register all commands in a static
sorted array.

The command pointers which are passed around aren't being modified -
in fact, no command pointer must be modified once it has been added to
the commandList.

No CamelCase and no struct typedefs.

Instead of manually calling memset(0) on the pcm_convert_state struct,
client code should use a library function from pcm_utils.c.  This way,
we can change the semantics of the struct easily.

Renamed all functions which were still in CamelCase.

No CamelCase, and a struct instead of a typedef.

Casting a pointer to some sort of integer and formatting it into a
string isn't valid.  A pointer derived from this hex string won't work
reliably.  Since ffmpeg doesn't provide a nice API for passing our
pointer, we have to think of a different hack: ffmpeg passes the exact
URL pointer to mpdurl_open(), and we can make this string part of a
struct.  This reduces the problem to casting the string back to the
struct.

This is still a workaround, but this is "sort of portable", unless the
ffmpeg people start messing with the URL pointer (which would be valid
according to the API definition).

Since ffmpeg svn r13528, you have to link with libavutil manually.

Since ffmpeg svn r12865, you have to include libavcodec/avcodec.h
instead of avcodec.h.  This cannot be checked at compile time, instead
we have to add a check to configure.ac.  Viliam's original ffmpeg
plugin was based on the newer ffmpeg library, while my Debian
installation had the older version.  My attempt to correct his include
statements wasn't correct after all.

{song,dir}vec_for_each each failed to gracefully handle deleted
files when iterating through.  While we were thread-safe, we
were not safe within the calling thread.  If a callback we
passed caused sv->nr to shring, our index would still increment;
causing files to stay in the database.

A way to test this is to remove 10 or so contiguous songs from a
>10 song directory.

Like the songvec nr_lock, only one lock is used for all
traversals since they're rarely changed.  This only
projects traversals, but not the individual structures
themselves.

We definitely don't modify them here.

This will make it easier to introduce locking

There was only one user of pathcpy_trunc(), which can be eliminated.

Again, GLib's version is more robust than ours.

GLib's g_path_get_basename() is much more reliable than
mpd_basename().  The latter could be tricked into an assertion
failure.

Identifiers with two leading underscores are reserved for the C
compiler's internal use.  Don't use them in the source.

Due to an off-by-one bug in map_fs_to_utf8(), the function returned
database paths with a leading slash.

[mk: use AC_SUBST instead of appending to MPD_CFLAGS / MPD_LIBS]

The macro name is HAVE_STRUCT_UCRED, not HAVE_UCRED.

The typedefs aren't using by anybody but struct input_stream.  Remove
them and declare the method type within struct input_stream.

The mpdurl_* code is internal, don't expose them.  Also don't
initialize struct members with NULL.

With heavy use of conditionals, I broke Makefile.am for the ancient
automake version 1.6.  Instead of supporting this automake version
forever, I'm removing support for it now.  Since automake isn't
required on the build machine, nobody should have a serious problem
with that.

Since mpd-mk has become the "official" MPD, the rename from commit
ba892cbc can be reverted.

client->permission is a bit set, and should be unsigned.

Reduce two temporary variables to only one.

There is no sense in using the kernel's send buffer size (SO_SNDBUF)
for MPD's send buffer.  Convert it into a static buffer of 4 kB.

Use a literal in the struct declaration, and sizeof(client->buffer)
everywhere else.  Also shrink the buffer from 40 kB to 4 kB.  The
buffer must only be large enough to hold one line of input, and 4 kB
is still more than enough.

The buffer pointers must not exceed the buffer size.

Use ssize_t instead of int.

Commit 6eb62e47 didn't obey partial lines correctly: when a line
wasn't finished in one read, the first part was ignored when the rest
arrived.

Patch 25b5d90e broke zeroconf compilation, because it assumed that
$with_zeroconf was set to "yes", although it can be either "bonjour"
or "avahi".

[mk: fixed indent, changed copyright statement, added autoconf test,
fixed includes paths, fixed 2 gcc warnings, don't close input stream
twice]

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

If a feature is disabled, don't compile the source file at all,
disable it completely in Makefile.am instead.

The nmemb argument isn't actually useful, and one of nmemb and size
was always passed as 1.  Remove it.

Provide a struct type which can be forward-declared.  The typedef
InputStream is deprecated now.