optional_depends    llvm '' '' 'use CLang' &&
optional_depends    gnutls \
                    "--enable-gnutls" \
                    "--disable-gnutls" \
                    "SSL/TLS support" &&

optional_depends    "fltk"                          \
                    "--with-gui=yes"                \
                    "--with-gui=no"                 \
                    "for compile with GUI"          &&
                    
optional_depends    "JPEG"                          \
                    "--disable-localjpeg"           \
                    "--enable-localjpeg"            \
                    "for shared jpeg library use"   &&
                    
optional_depends    "libpng"                        \
                    "--disable-localpng"            \
                    "--enable-localpng"             \
                    "for shared png library use"    &&
                    
optional_depends    "zlib"                          \
                    "--disable-localzlib"           \
                    "--enable-localzlib"            \
                    "for shared zlib library use"

