spkg-configure.m4 for pcre should test for UTF support etc

[dimpase]

one can build an insufficiently powerful pcre, see #27284
So we better check that it has all the goodies needed.

Component: build: configure

Issue created by migration from https://trac.sagemath.org/ticket/27936

[embray]

comment:1

It looks to me that it's sufficient to run

$ pcretest -C utf

which strangely both outputs 1 if UTF is supported, and the exit code also is 1 if supported. So pcretest both prints the results of these checks and returns them as non-POSIX exit codes.

But fine, this means we just need to

1. Check for pcretest

2. Run

if test `pcretest -C utf` -eq 1`; then
...

I'd say if pcretest is absent just don't assume the system lib can be used.

[embray]

comment:2

As the Sage-8.8 release milestone is pending, we should delete the sage-8.8 milestone for tickets that are not actively being worked on or that still require significant work to move forward. If you feel that this ticket should be included in the next Sage release at the soonest please set its milestone to the next release milestone (sage-8.9).

[mkoeppe]

Outdated, package pcre was removed