optional_depends %JPEG  "--with-jpeglib" "--without-jpeglib" "for jpeg graphics support"
optional_depends libpng "--with-libpng"  "--without-libpng"  "for libpng support"
optional_depends %X     "--with-x"       "--without-x"       "use the X Window System"
optional_depends tk     "--with-tcltk"   "--without-tcltk"   "for gui, recommended"
optional_depends icu4c  "--with-ICU"     "--without-ICU"     "for Unicode support"
optional_depends cairo  "--with-cairo"   "--without-cairo"   "for cairo (and pango) support"
optional_depends lapack "--with-lapack"  "--without-lapack"  "If y, use system lapack"

optional_depends pcre   "--with-system-pcre"  "--without-system-pcre"  "for pcre support"
optional_depends bzip2  "--with-system-bzlib" "--without-system-bzlib" "for file compression support"
optional_depends zlib   "--with-system-zlib"  "--without-system-zlib"  "for zlib support"
