Fix error messages related to undefined symbols in lwlink Make lwlink not complain about seciton base and length symbols. Also silence duplicate complaints about undefined symbols. There is no need to complain about undefined symbols during the file/section resolution stage! If they are truly undefined, they'll still be undefined at the reference resolution stage.

See the file GPL3 for a copy of the GNU General Public License, version 3,
under which the majority of this distribution is licensed.

Some specific source files, including many of those in the lwcc subdirectory
are licensed differently. See each individual file for specific details.