Log Message:
Update to 6.7.1. From the git log:

- Solaris has a function named sig2str. Rename ours oksh_sig2str.
- Pull in latest upstream code, which is #43 from Michael Forney.
- Make BINDIR and MANDIR actually depend on PREFIX.
- Variables have $'s.
- Older Linux has clock_gettime in librt; check for that.
- configure: improve clock_gettime diagnostic messages.
- HP-UX support.
- Add --enable-lto for those who want link-time optimization.
- Update to latest OpenBSD code.
- Make cross compiling a real possibility, with instructions.
- Fix typo.
- For loop initial declarations is a better C99 check for older gcc.
- Update from OpenBSD.
- Separate out compilation and linking in configure tests.
- Only add -std=gnu99 if using --no-thanks.
- If using --no-thanks and you didn't specify the environment
- --no-thanks isn't just for cross compiling
- Default to ST_MTIM when using --no-thanks