optional_depends zlib    "--with-zlib"          "--without-zlib"        "for compression support"
optional_depends bzip2   " --with-bzlib"        " --without-bzlib"      " for bzip compression support"
optional_depends openssl "--with-openssl"       "--without-openssl"     "for openssl support"
optional_depends boost   "--with-boost"         "--without-boost"       "for boost support"
optional_depends doxygen "--enable-doxygen-doc" "--disable-doxygen-doc" "for documentation"
optional_depends apache-log4cxx "--with-log4cxx" "--without-log4cxx"    "for logging support"
