depends X11-LIBS  &&
optional_depends  "zlib"              \
                  "--enable-zlib"     \
                  "--disable-zlib"    \
                  "for zlib support"  &&
optional_depends  "bzip2"             \
                  "--enable-libbz2"   \
                  "--disable-libbz2"  \
                  "for bzip2 support"
