Remove mpg123 reference from build system.

TODO: macOS/iOS xcodeproj

platform/unix/configure.ac

@@ -55,7 +55,6 @@ with_clean_luaversion=`printf ${with_luaversion} | sed 's/\.//g'`
 m4_include([configure-modules-pre.ac])
 
 # Other features that can be enabled/disabled
-AC_ARG_ENABLE([mpg123], AC_HELP_STRING([--disable-mpg123], [Disable mp3 support, for patent-free builds]), [], [enable_mpg123=yes])
 AC_ARG_ENABLE([gme], AC_HELP_STRING([--enable-gme], [Enable GME support, for more chiptuney goodness]), [], [enable_gme=no])
 
 # Dependencies we always use
@@ -71,12 +70,9 @@ AS_VAR_IF([enable_module_font], [yes], [ACLOVE_DEP_FREETYPE2], [])
 AS_VAR_IF([enable_module_sound], [yes], [
 	ACLOVE_DEP_LIBMODPLUG
 	ACLOVE_DEP_VORBISFILE
-], [enable_mpg123=no])
+], [])
 AS_VAR_IF([enable_module_video], [yes], [ACLOVE_DEP_THEORA], [])
 AS_VAR_IF([enable_gme], [yes], [ACLOVE_DEP_GME], [])
-AS_VAR_IF([enable_mpg123], [no],
-	  AC_DEFINE([LOVE_NOMPG123], [], [Build without mpg123]),
-	  [ACLOVE_DEP_MPG123])
 
 # Add flags for optional libraries
 AC_ARG_ENABLE([library-enet], [  --disable-library-enet    Turn off library enet], [], [enable_library_enet=yes])
@@ -117,7 +113,6 @@ AS_VAR_IF([enable_exe], [no], [], #else
 	  AC_DEFINE([LOVE_BUILD_EXE], [], [Skip building launcher]))
 
 AM_CONDITIONAL([LOVE_BUILD_EXE], [test "x$enable_exe" != xno])
-AM_CONDITIONAL([LOVE_NOMPG123], [test "x$enable_mpg123" = xno])
 AM_CONDITIONAL([LOVE_TARGET_OSX], [test "x$enable_osx" != xno])
 
 # Automatic script file rebuilding