+##### openal, alut #####
+website="http://connect.creativelabs.com/openal/"
+AC_CHECK_HEADERS([AL/al.h AL/alut.h],,
+ [missing=yes
+ echo "***** Missing OpenAL headers ($website) *****"])
+AC_SEARCH_LIBS([alEnable], [openal openal32],,
+ [missing=yes
+ echo "***** Missing libopenal ($website) *****"])
+AC_SEARCH_LIBS([alutInit], [alut],,
+ [missing=yes
+ echo "***** Missing libalut ($website) *****"])
+
+##### SDL_image #####
+website="http://www.libsdl.org/projects/SDL_image/"
+AC_CHECK_HEADERS([SDL/SDL_image.h],,
+ [missing=yes
+ echo "***** Missing SDL_image header ($website) *****"])
+AC_SEARCH_LIBS([IMG_Load], [SDL_image],,
+ [missing=yes
+ echo "***** Missing libSDL_image ($website) *****"])
+
+##### libvorbis #####
+website="http://www.xiph.org/downloads/"
+AC_CHECK_HEADERS([vorbis/codec.h vorbis/vorbisfile.h],,
+ [missing=yes
+ echo "***** Missing vorbis headers ($website) *****"])
+AC_SEARCH_LIBS([ov_open], [vorbisfile],,
+ [missing=yes
+ echo "***** Missing libvorbisfile ($website) *****"])
+
+##### librt (optional) #####
+AC_SEARCH_LIBS([clock_gettime], [rt],
+ [AC_DEFINE([HAVE_CLOCK_GETTIME], 1,
+ [Define to 1 if you have the 'clock_gettime' function.])])