Can drop extraneous Req's from -devel: 
 
Requires: esound-devel 
Requires: glib2-devel 
Requires: libvorbis-devel 
Requires: audiofile-devel 
Requires: alsa-lib-devel 
 
By adding to %install: 
## remove references to optional external libraries in .la files 
# libmad 
sed -i -e "s@-lmad@@g"                $RPM_BUILD_ROOT%{_libdir}/*.la 
sed -i -e "s@%{_libdir}/libmad.la@@g" $RPM_BUILD_ROOT%{_libdir}/*.la 
# ogg 
sed -i -e "s@-lvorbisfile@@g"   $RPM_BUILD_ROOT%{_libdir}/*.la 
sed -i -e "s@-lvorbisenc@@g"    $RPM_BUILD_ROOT%{_libdir}/*.la 
sed -i -e "s@-lvorbis@@g"       $RPM_BUILD_ROOT%{_libdir}/*.la 
sed -i -e "s@-logg@@g"          $RPM_BUILD_ROOT%{_libdir}/*.la 
# alsa-lib/asound 
sed -i -e "s@-lasound@@g"       $RPM_BUILD_ROOT%{_libdir}/*.la 
# audiofile 
sed -i -e "s@-laudiofile@@g"    $RPM_BUILD_ROOT%{_libdir}/*.la 
# esound/esd 
sed -i -e "s@-lesd@@g"                $RPM_BUILD_ROOT%{_libdir}/*.la 
sed -i -e "s@%{_libdir}/libesd.la@@g" $RPM_BUILD_ROOT%{_libdir}/*.la 
# glib 
sed -i -e "s@@g"  $RPM_BUILD_ROOT%{_libdir}/*.la 
sed -i -e "s@@g"  $RPM_BUILD_ROOT%{_libdir}/*.la 
sed -i -e "s@@g"     $RPM_BUILD_ROOT%{_libdir}/*.la 
# png/zlib 
sed -i -e "s@-lpng -lz @@g"     $RPM_BUILD_ROOT%{_libdir}/*.la