Rationale: vanilla libid3tag does not have any pkg-config stuff
and fails to detect because symbols from libz are not found.

Needed by ax_append_link_flags.m4.

Produce a smaller binary by removing all unused functions.

We'll add some C++11 code soon.

Use standard scripts instead of MPD's custom implementation.

Don't use MPC_CFLAGS, MPD_LIBS.

Add M4 function MPD_AUTO_PKG_LIB for pkg-config with AC_CHECK_LIB
fallback.

Use "printf" instead.

Fixes autotools warnings.

Add optional third value to results() to allow for non "yes" answers which are
considered positive.

This commit adds a new pretty print menu, we've (far) outgrown the old
menu which because hard to traverse.

Use MPD_AUTO_RESULT().  Don't force libwrap by default.

Append $FAAD_LIBS to $LIBS when detecting libmp4ff.  $FAAD_LIBS may
contain an important -L flag.

The M4 function AM_PATH_LAME (m4/lame.m4) defined a configure flag
named "--disable-lametest".  This is redundant with configure.ac's
--disable-lame-encoder, and specifying both options may break the
build.  Since AM_PATH_LAME is only called when the encoder plugin is
enabled, we can safely remove that --disable-lametest option.

This function checks whether a prerequisite for a feature was found.

When MPD_AUTO_DISABLED prints a fatal error message, include the
feature name.  This might be an important piece of information for the
user, just in case the preceding line doesn't tell him.

In the MPD_AUTO_DISABLED() function, I forgot to check for "explicitly
disabled".

MPD_AUTO_PKG() runs pkg-config and then forwards control to
MPD_AUTO_RESULT().  This is a commonly used short cut.

This patch adds a small autoconf M4 library which deals with
auto-detected features.  The default for those features is "auto",
which is like the old default: if the library is present on the
system, enable the feature, disable otherwise.  If the user explicitly
enables that feature (--enable-alsa), and the library is not present,
configure must fail, because it cannot fulfill the request.

Most strings have no capitalization at the beinning, make all strings
non-capital.

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

Both are unused.

By default, glibc 2.8 hides struct ucred behind the _GNU_SOURCE
macro.  I don't want to enable that globally, because it may encourage
the use of non-portable functions.  Test if "struct ucred" is
available, and enable _GNU_SOURCE if required.

For details about that issue, see glib's bug database:

 http://sources.redhat.com/bugzilla/show_bug.cgi?id=6545

Detect the following libraries with pkg-config: libshout, libid3tag,
libmad.

This patch fixes several imports to use pkg-config instead of certain
esoteric tests.

This is needed for people that don't use any of the following:
JACK, ALSA, libmikmod, Shout.

[mk: moved this patch after "Refactor and cleanup of shout Ogg and MP3
audio outputs".  The original commit message follows, although it is
outdated:]

Creation of shout_mp3 audio output plugin. Basically I just copied the
existing shout plugin and replaced ogg with lame. Uses lame for mp3
encoding. Next step is to pull common functionality out of each shout
plugin and share it between them.

Configuration options for "shout_mp3" are the same as for "shout".

Previously, it was not possible to check for e.g. "-std=c99".

needed for compatibility with older gcc.  Also, threw in
some warnings for things I find offensive
(declaration-after-statement, shadow)

git-svn-id: https://svn.musicpd.org/mpd/trunk@7299 09075e82-0dd4-0310-85a5-a0d7c8717e4f

argument.

git-svn-id: https://svn.musicpd.org/mpd/trunk@6324 09075e82-0dd4-0310-85a5-a0d7c8717e4f

We will restore compatibility with the old API in the
next few commits; along with OggFLAC support.

git-svn-id: https://svn.musicpd.org/mpd/trunk@5110 09075e82-0dd4-0310-85a5-a0d7c8717e4f