CONFIGURE: Add libmpeg2 as an optional dependency again

configure

@@ -113,6 +113,7 @@ _seq_midi=auto
 _sndio=auto
 _timidity=auto
 _zlib=auto
+_mpeg2=auto
 _sparkle=auto
 _png=auto
 _theoradec=auto
@@ -924,6 +925,9 @@ Optional Libraries:
   --with-zlib-prefix=DIR   Prefix where zlib is installed (optional)
   --disable-zlib           disable zlib (compression) support [autodetect]
 
+  --with-mpeg2-prefix=DIR  Prefix where libmpeg2 is installed (optional)
+  --enable-mpeg2           enable mpeg2 codec for cutscenes [autodetect]
+
   --with-opengl-prefix=DIR Prefix where OpenGL (ES) is installed (optional)
   --disable-opengl         disable OpenGL (ES) support [autodetect]
 
@@ -1004,6 +1008,8 @@ for ac_option in $@; do
 	--disable-sparkle)        _sparkle=no     ;;
 	--enable-nasm)            _nasm=yes       ;;
 	--disable-nasm)           _nasm=no        ;;
+	--enable-mpeg2)           _mpeg2=yes      ;;
+	--disable-mpeg2)          _mpeg2=no       ;;
 	--disable-png)            _png=no         ;;
 	--enable-png)             _png=yes        ;;
 	--disable-theoradec)      _theoradec=no   ;;
@@ -1043,6 +1049,11 @@ for ac_option in $@; do
 		FLUIDSYNTH_CFLAGS="-I$arg/include"
 		FLUIDSYNTH_LIBS="-L$arg/lib"
 		;;
+	--with-mpeg2-prefix=*)
+		arg=`echo $ac_option | cut -d '=' -f 2`
+		MPEG2_CFLAGS="-I$arg/include"
+		MPEG2_LIBS="-L$arg/lib"
+		;;
 	--with-alsa-prefix=*)
 		arg=`echo $ac_option | cut -d '=' -f 2`
 		ALSA_CFLAGS="-I$arg/include"
@@ -3460,6 +3471,49 @@ fi
 define_in_config_if_yes "$_zlib" 'USE_ZLIB'
 echo "$_zlib"
 
+#
+# Check for LibMPEG2
+#
+echocheck "libmpeg2 >= 0.3.2"
+if test "$_mpeg2" = auto ; then
+	_mpeg2=no
+	cat > $TMPC << EOF
+typedef signed $type_1_byte int8_t;
+typedef signed $type_2_byte int16_t;
+typedef signed $type_4_byte int32_t;
+
+typedef unsigned $type_1_byte uint8_t;
+typedef unsigned $type_2_byte uint16_t;
+typedef unsigned $type_4_byte uint32_t;
+
+#include <mpeg2dec/mpeg2.h>
+int main(void) {
+	/* mpeg2_state_t first appears in 0.4.0 */
+	mpeg2_state_t state;
+
+		#ifdef MPEG2_RELEASE
+		if (MPEG2_RELEASE >= MPEG2_VERSION(0, 3, 2))
+			return 0;
+	#endif
+	return 1;
+}
+EOF
+
+	if test -n "$_host"; then
+		# don't execute while cross compiling
+		cc_check $MPEG2_CFLAGS $MPEG2_LIBS -lmpeg2 && _mpeg2=yes
+	else
+		cc_check_no_clean $MPEG2_CFLAGS $MPEG2_LIBS -lmpeg2 && $TMPO$HOSTEXEEXT && _mpeg2=yes
+		cc_check_clean
+	fi
+fi
+if test "$_mpeg2" = yes ; then
+	INCLUDES="$INCLUDES $MPEG2_CFLAGS"
+	LIBS="$LIBS $MPEG2_LIBS -lmpeg2"
+fi
+define_in_config_if_yes "$_mpeg2" 'USE_MPEG2'
+echo "$_mpeg2"
+
 #
 # Check for Sparkle if updates support is enabled
 #