depends  gmp  &&
depends  zlib  &&

case $CURL_SSL in
 gnutls)
     depends  gnutls     \
     "--with-gnutls \
      --without-ssl --without-nss --without-polarssl"
     ;;
 libressl | openssl)
     depends  SSL         \
     "--with-ssl \
      --without-gnutls --without-nss --without-polarssl"
     ;;
 nss) 
     depends  -sub PEM nss         \
     "--with-nss \
      --without-gnutls --without-ssl --without-polarssl"
     ;;
 polarssl)
     depends  polarssl     \
     "--with-polarssl \
      --without-ssl --without-nss --without-gnutls"
     ;;
 none)
   OPTS+=" --without-gnutls --without-nss --without-ssl"
    ;;
esac &&

if [[ "$CURL_SSL" == "none" ]]; then
   OPTS+="  --without-ca-bundle"
else
  depends ca-certificates "--with-ca-bundle=$INSTALL_ROOT/etc/ssl/certs/ca-certificates.crt"
fi &&

optional_depends  krb5   \
                  "--with-gssapi "    \
                  "--without-gssapi " \
                  "GSSAPI support" &&

optional_depends  libssh2                              \
                  "--with-libssh2"   \
                  '--without-libssh2'                  \
                  "for SSH (SCP and SFTP) support"     &&

optional_depends rtmpdump \
                 "" \
                 '--without-librtmp' \
                 "for RTMP streaming media support" &&

optional_depends  c-ares                                                       \
                  "--enable-ares=$INSTALL_ROOT/usr"                            \
                  '--disable-ares'                                             \
                  "to performs DNS requests and name resolves asynchronously"  &&

optional_depends  libidn                                   \
                  "--with-libidn=$INSTALL_ROOT/usr"        \
                  '--without-libidn'                       \
                  'for International Domain Name support'  &&

if [[ "$CURL_SSL" != "none" ]]; then
  optional_depends  openldap                                             \
                    '--enable-ldap --enable-ldaps'                       \
                    '--disable-ldap --disable-ldaps'                     \
                    'for Lightweight Directory Access Protocol support'
else
  optional_depends  openldap                                             \
                    '--enable-ldap'                                      \
                    '--disable-ldap'                                     \
                    'for Lightweight Directory Access Protocol support'
fi &&

optional_depends  nghttp2                \
                  "--with-nghttp2"       \
                  "--without-nghttp2"    \
                  "for HTTP/2 support" &&
optional_depends brotli \
                 "--with-brotli" \
                 "--without-brotli" \
                 "Brotli compression"