[release-1.6] Prevent PCRE from needing a rebuild/reconf.

[Sacha0]

This commit reorders a couple touches in deps/pcre.mkl. Those touches are
intended to prevent patch application from triggering rebuild/reconf.
The present ordering doesn't quite succeed in that objective; patch
application triggers rebuild. On systems with compatible autotools,
the rebuild succeeds and the build is nonetheless happy. On systems
with incompatible versions of autotools, however, the build fails for
need of a reconf. The reordering in this commit prevents the rebuild.

Co-Authored-By: Rob Vermaas <rob.vermaas@gmail.com>

Applies only to release-1.6; the relevant patches and touches are gone on master :).

@KristofferC, let me know if I should target some other branch :).

cc @rbvermaa

[staticfloat]

I think we usually target backports-release-1.6, but other than that this looks good to me!

[Sacha0]

I think we usually target backports-release-1.6, but other than that this looks good to me!

Yes, I targeted release-1.6 because no backports-release-1.6 exists at the moment, the most recent backports branch having recently been merged. Should I create a new backports-release-1.6 branch for this patch to sit on for however long, or should we merge into release-1.6 directly? :)

[KristofferC]

Included in #40150

[Sacha0]

Thanks Kristoffer! :)