Exclude multilib directories in pcre2-config

[NWilson]

I've noticed that many Linux distributions carry a patch to disable this block of code in pcre2-config.

I believe that few people actually use this script. However, if any downstream distributors are going to the trouble of including a patch, it's probably better to just accept that patch.

[NWilson]

An alternative to this PR would be to consider removing pcre2-config entirely. Perhaps it's completely unused. I have no way of knowing this however.

[NWilson]

I did a quick bit of research. There are many hits on GitHub for pcre2-config, including some relatively major packages. Apparently people find it easier to use than pkg-config? In any case, there's evidence there that removing it could cause disruption, which I'm not willing to do at this time (or ever).

Debian has 11000 packages matching the package name *-dev. Of those, 150 provide a file with the name /usr/bin/*-config (and another 150 packages with names not matching *-dev; some of those are presumably config utilities for users, rather than library helpers for developers). These include some relatively well-known projects, like /usr/bin/libpng-config, or /usr/bin/krb5-config, and many more.

In 2025, we probably wouldn't create a new config script, but given that it exists, I think pcre2-config has to stay.

apt-cache search -n -- '-dev$' | grep '^lib.*-dev - ' | sort -u
apt-file -x search '/usr/bin/.*-config$'