Detection of ALSA support in configure test

[Moritz Muehlenhoff <jmm@inutil.org>]

Dear kfreebsd developers,

I'm looking into a build failure of the scummvm package. (#600655)
It uses  the following configure snippet to detect the availability
of ALSA:

-----------------------------
#
# Check for ALSA
#
echocheck "ALSA >= 0.9"
if test "$_alsa" = auto ; then
        _alsa=no
        cat > $TMPC << EOF
#include <alsa/asoundlib.h>
int main(void) { return (!(SND_LIB_MAJOR==0 && SND_LIB_MINOR==9)); }
EOF
        cc_check $LDFLAGS $CXXFLAGS $ALSA_CFLAGS $ALSA_LIBS -lasound && _alsa=yes
fi
if test "$_alsa" = yes ; then
        _def_alsa='#define USE_ALSA'
        LIBS="$LIBS $ALSA_LIBS -lasound"
        INCLUDES="$INCLUDES $ALSA_CFLAGS"
else
        _def_alsa='#undef USE_ALSA'
fi
echo "$_alsa"
-----------------------------

This test remained the same for 1.1.1, 1.2.0 and 1.2.1. While it
worked fine with the kfreebsd as of 1.1.1 (uploaded 8th May 2010),
it fails for scummvm 1.2.0 onwards (uploaded in October and December).

Did anything change wrt libasound on the kfreebsd side? Although I
could pass "--disable-alsa" for the kfreebsd build, I would prefer
to fix the underlying bug and have the configure script detect ALSA
properly. Also, if this is a standard autoconf test it might be worth
getting it fixed in general.

Cheers,
        Moritz