Possible bug/issue in autoconf when configuring --with-prrte=internal

[dalcinl]

I'm running configure --with-prrte=internal ... out of source, and getting the following output:

configure: ===== done with 3rd-party/prrte configure =====
checking for internal PRRTE RST files... not found
checking for prte.h... no
../ompi/configure: line 66906: test: -eq: unary operator expected

After checking my GitHub Actions logs, I noticed the same output in both main and v5.0.x branches.
https://github.com/mpi4py/mpi4py-testing/actions/runs/7770441998/job/21190639527#step:6:3478
https://github.com/mpi4py/mpi4py-testing/actions/runs/7770441998/job/21190639618#step:6:3362

[janjust]

Looks like a doc issue

[jsquyres]

Looks like a doc issue

Looking at this after the OMPI call today, I don't think that this is a docs issue.

The checking for internal PRRTE RST files message is in _OMPI_SETUP_PRRTE_INTERNAL, and the checking for prte.h is in _OMPI_SETUP_PRRTE_EXTERNAL, both of which are called from this code block.

I'm out of time, but my guess is that the error is an empty shell variable in the latter part of the block that executes the EXTERNAL macro, or in a code block that comes shortly after that. Shouldn't be too hard to track down.

This is evidently not a fatal error, but it is something that should be cleaned up.