Moved generic compiler options to AM_CFLAGS.  MPD_CFLAGS/MPD_LIBS will
hopefully fade away one day, in favor of more fine-grained variables.

Removed superfluous commas.

Recursive Makefiles are inefficient and error prone (no proper way to
declare dependencies).  Since there's no disadvantage in having one
single Makefile, let's do it.

Removed shout's encoder plugin API in favor of the new generic encoder
plugin API.

This new LAME encoder plugin is based on the existing shout_mp3.c
plugin.

This new vorbis encoder plugin is based on the existing shout_ogg.c
plugin.

The new generic encoder API will replace shout's custom encoder API.

The configure.ac script does not care about the host architecture, it
only cares about the OS.  Use ${host_os} instead of ${host} to
simplify the matching expressions.

Without AC_CANONICAL_HOST, ${host_os} etc. are not defined.

The switch syntax is "--enable-test".  There are no test programs yet.

Use faacDecInit2() instead of AudioSpecificConfig() to detect the AAC
track in the MP4 file.  This has a great advantage: it initializes the
libfaad decoder, which the caller would normally do anyway - but now
we can go without the AudioSpecificConfig() call.  When decoder==NULL
(called from mp4_tag_dup()), fall back to a mp4ff_get_track_type()==1
check, like other audio players do.

When configured with --enable-documentation, use doxygen.

Currently, only the sidplay decoder plugin requires C++, and in all
other cases, MPD could build well without a C++ compiler.
Unfortunately, autoconf/automake are confused when we have a
conditional AC_PROG_CXX check.  We could add lots of workarounds for
individual problems, but let's just always require a C++ compiler, and
forget about this autotools limitation.

There are a few problems left in this plugin:

- fluidsynth decodes in real time, while MPD prefers to buffer as
  quickly as possible; as a workaround, this plugin uses a timer
  object to synchronize with real-time playback

- I don't know yet how fluidsynth tells me when the song has ended

- the "soundfont" configuration setting is not yet documented, and it
  will likely change soon (in favor of a per-decoder configuration
  block)

When the sidplay plugin is disabled, "./configure" does not look for
the C++ compiler.  This creates an odd situation: automake requires
the am__fastdepCXX conditional, although configure did not generate
it.  Work around this autotools limitation by manually disabling
am__fastdepCXX.

Don't define HAVE_FFMPEG if the ffmpeg libraries were found via
pkg-config, but ffmpeg support was disabled because
avcodec_decode_audio2() is not available.

The protocol has been extended since MPD 0.14: playlist ranges,
stickers.  About time to give the protocol a new version number!

Disable the HTML documentation generator by default.  Most users will
pick it from the web site.

jack_set_info_function() is not provided by older libjack versions.
Attempt to detect if it is available.

MMS streaming is experimental; sync the default value with the help
text.

This patch implements the MMS protocol, by using libmms.  It is quite
experimental: it does not support seeking yet, and it is currently
using synchronous I/O, which causes MPD to hang while waiting for the
server.

When tremor (libvorbisidec) is used, HAVE_OGGVORBIS was not defined.

MPD will (optionall) use sqlite databases in the future.  Add a
configure option to enable that.  There is no code yet to really use
sqlite, so the practical use of this patch is limited.

Declare and initialize MPD_LIBS and MPD_CFLAGS before the "OS specific
defaults" section.

Zeroconf, curl, libsamplerate.  No libid3tag for now, because
libid3tag should be automatically disabled when no decoders using it
are enabled.

Don't separate basic options from their according tests.  Due to lots
of interdependencies, we won't do that for the plugins yet.

Print input plugins first, then archive, metadatab, decoder,
converter, encoder, output plugins.

Initialize the CFLAGS (warnings, errors) after all the libraries,
because some library checks may be broken with -Werror or -pedantic.

AC_CHECK_HEADERS defines HAVE_LOCALE_H, so we don't have to manually
define HAVE_LOCALE.

First do the checks for mandatory stuff (libc features, glib,
pkg-config), then all the options.

Don't check for inttypes.h and langinfo.h.

Fix a typo.

libid3tag comes without a pkg-config file, and it is usually added by
distribution packages.  For those without .pc file, attempt to
auto-detect the library with AC_CHECK_LIB.

All socket functions are provided by ws2_32.dll.

This is a rather huge patch, which unfortunately cannot be splitted.

Instead of using our custom ioops.h library, convert everything to use
the GLib main loop.