Changes

check-typo: be more liberal with url

(cherry picked from commit f6649d7dfcdf963ec2f1834a7a97b64526d3a0ae)

Merge pull request #13749 from tmcgilchrist/patch-1

Add Linux ARM64 build

(cherry picked from commit 4bfea21fe3137018dee0454c9aa0e23bfbf2ea9c)

Unified CI cherry-pick: PR#13724

(cherry picked from commit 5f6587e50d209ea51acf04ea2eacc3437a95cc3e)

Merge pull request #13840 from dra27/apt-update

Always call `apt-get update` in CI before installing

(cherry picked from commit 2f39689352ba75fdb4cddd6f3014b11e0c42fb14)

Merge pull request #13857 from MisterDA/gha-cygwin-make

GHA: small improvements for Cygwin and Linux actions
(cherry picked from commit 2d3138a5d04affc175a8a0a8ac0cbd1502a5e32c)

Merge pull request #13954 from dra27/cygwin

Pin Cygwin to 3.6.1 until AppVeyor updates

(cherry picked from commit 787687e31bd4e95a6232a53b77439bf56b503aee)

Fix hygiene check for generating `configure` (#13935)

* Allow check-configure.sh to be run locally

* Re-bash the autoconf test

* Simplify - and correct - check-configure.sh

The script contained an unused feature to be able to check PRs as one -
this is never wanted, as we should always be checking that every commit
has a valid committed configure script.

The mechanism for checking whether commits should be tested is shifted
back to the actual trawl of the log. This is both simpler (because it
can be done with a simple file list) but also fixes a bug, since commits
which _didn't_ update configure could reset a failure from an earlier
commit.

* Wrong parameter checked in check-configure.sh

* Review

(cherry picked from commit 4b905fd93d349f41c416f9a06bd2433425fc67b6)

Merge pull request #14013 from dra27/more-ci-tweaks

GHA: add an optional wider test matrix (Cygwin, static, minimal, etc.)
(cherry picked from commit 96b56fd4c822c92b4b81ff4ac7903ae8afb16a52)