Cleanup: rename linker/archiver to indexer in featureless make and tweak bootstrap.sh.

Cleanup: rename linker/archiver to indexer in featureless make and tweak bootstrap.sh.

The linker program 'ar' creates an archive which is essentially an index.
By switching the words from linker and archiver to indexer, I believe that I can avoid terminology conflicts.
This avoids conflicting the 'linker' in terms of 'ar' and the 'linker' in terms of 'ln'.
This avoids conflicting the 'archiver' in terms of 'ar' and the 'archiver' in terms of 'bzip2'.

Use "return" instead of "exit" in bootstrap.sh.