libpftputil @0.3 mojave build fails due to unrecognized -syslibroot option to clang

[rlhamil]

:info:build /usr/bin/clang -r -keep_private_externs -nostdlib -o .libs/libpftputil.0.0.3.dylib-master.o editconf.lo pftp_client.lo pftp_default.lo pftp_item.lo pftp_getconf.lo gethosts.lo getline.lo pftputil.lo parse_utils.lo patternmatch.lo pftp_que.lo set_utils.lo setconf.lo sethosts.lo pftp_settings.lo pftputil_settings.lo str.lo && /usr/bin/clang -dynamiclib -flat_namespace -undefined suppress -o .libs/libpftputil.0.0.3.dylib .libs/libpftputil.0.0.3.dylib-master.o -L/opt/local/lib -lssl -lcrypto -lresolv -lc -headerpad_max_install_names -syslibroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk -headerpad_max_install_names -syslibroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk -install_name /opt/local/lib/libpftputil.0.dylib -compatibility_version 1 -current_version 1.3

:info:build clang: error: unknown argument: '-syslibroot' :info:build clang: error: unknown argument: '-syslibroot' :info:build make[2]: * [libpftputil.la] Error 1 :info:build make[2]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_net_libpftputil/libpftputil/work/libpftputil-0.3/src' :info:build make[1]: * [all] Error 2 :info:build make[1]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_net_libpftputil/libpftputil/work/libpftputil-0.3/src' :info:build make: * [all-recursive] Error 1 :info:build make: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_net_libpftputil/libpftputil/work/libpftputil-0.3' :info:build Command failed: cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_net_libpftputil/libpftputil/work/libpftputil-0.3" && /usr/bin/make -j8 -w all :info:build Exit code: 2 :error:build Failed to build libpftputil: command execution failed