depends  tc2  &&
optional_depends  "xorg-libs"       \
                  "--with-x"       \
                  "--without-x"    \
                  "to be able to build the GIF reader module"  &&
optional_depends  "GIFLIB"         \
                  "--enable-gif"   \
                  "--disable-gif"  \
                  "for a GIF image reader module"  &&
optional_depends  "libpng"         \
                  "--enable-png"   \
                  "--disable-png"  \
                  "for a PNG image reader/writer module"  &&
optional_depends  "libmng"         \
                  "--enable-mng"   \
                  "--disable-mng"  \
                  "for a MNG image reader module"  &&
optional_depends  "curl"            \
                  "--enable-http"   \
                  "--disable-http"  \
                  "for a HTTP file reader module"  &&
optional_depends  "SSL"         \
                  "--enable-netq"   \
                  "--disable-netq"  \
                  "for a networking module"

.