With the symlinked build it's only renaming 'coreutils' to
'gcoreutils' and leaving all the actual command symlinks alone.
Instead of custom renaming scripts, let's use --program-prefix
from the autotools kitchen sink. This has the nice(?) bonus that
the manpages also get prefixed with 'g' now.
The build system refuses to enable both single-binary build and
--program-prefix - but the symlink-based single-binary build couldn't
possibly work either (as it will be looking at "$0" for which command
to execute).
659f75bfcd