+##### SDL #####
+website="http://www.libsdl.org/"
+PKG_CHECK_MODULES([SDL], [sdl],
+ [LIBS="$LIBS $SDL_LIBS"
+ CFLAGS="$CFLAGS $SDL_CFLAGS"
+ CXXFLAGS="$CXXFLAGS $SDL_CFLAGS"],
+ [missing=yes
+ echo "***** Missing SDL ($website) *****"])
+
+##### opengl, glu #####
+website="http://www.mesa3d.org/"
+PKG_CHECK_MODULES([OPENGL], [gl glu],
+ [LIBS="$LIBS $OPENGL_LIBS"
+ CFLAGS="$CFLAGS $OPENGL_CFLAGS"
+ CXXFLAGS="$CXXFLAGS $GLU_CFLAGS"],
+ [missing=yes
+ echo "***** Missing OpenGL ($website) *****"])
+
+##### liblua #####
+website="http://www.lua.org/"
+PKG_CHECK_MODULES([LUA], [lua],
+ [LIBS="$LIBS $LUA_LIBS"
+ CFLAGS="$CFLAGS $LUA_CFLAGS"
+ CXXFLAGS="$CXXFLAGS $LUA_CFLAGS"],
+ [missing=yes
+ echo "***** Missing liblua ($website) *****"])
+
+##### libpng #####
+website="http://www.libpng.org/pub/png/libpng.html"
+PKG_CHECK_MODULES([PNG], [libpng],
+ [LIBS="$LIBS $PNG_LIBS"
+ CFLAGS="$CFLAGS $PNG_CFLAGS"
+ CXXFLAGS="$CXXFLAGS $PNG_CFLAGS"],
+ [missing=yes
+ echo "***** Missing libpng ($website) *****"])
+
+##### openal #####
+website="http://connect.creativelabs.com/openal/"
+PKG_CHECK_MODULES([OPENAL], [openal],
+ [LIBS="$LIBS $OPENAL_LIBS"
+ CFLAGS="$CFLAGS $OPENAL_CFLAGS"
+ CXXFLAGS="$CXXFLAGS $OPENAL_CFLAGS"],
+ [missing=yes
+ echo "***** Missing OpenAL ($website) *****"])
+
+##### libvorbis #####
+website="http://www.xiph.org/downloads/"
+PKG_CHECK_MODULES([VORBIS], [vorbisfile],
+ [LIBS="$LIBS $VORBIS_LIBS"
+ CFLAGS="$CFLAGS $VORBIS_CFLAGS"
+ CXXFLAGS="$CXXFLAGS $VORBIS_CFLAGS"],
+ [missing=yes
+ echo "***** Missing libvorbisfile ($website) *****"])
+
+##### GTK+ 2.0 #####
+if test x$gtk = xyes