Revert the last commit, it made the Bruce filter flip:

Revert the last commit, it made the Bruce filter flip:

PR7402 was even less suitable for committing almost verbatim than at
first appearance.  Rev.1.9 of primes.c has at least the following defects.

- no update for man page.
- no update for usage string.
- blowing away of a previous commit to change EOF to -1 in getopt() test.
- blowing away of a previous commit to fix printf format errors.
- new printf format errors.
- one gratuitous ANSIism.
- two style bugs.
- ... and a partition in a pear tree.

PR:		7402