MSVC: Teach find_library to consider the 'libfoo.a' naming convention

When targeting the GNU ABI, we consider `.a` libraries first but also
accept `.lib`.  For symmetry, when targeting the MSVC ABI, we now
consider `.lib` first but also accept `.a`.

This adds support for meson-generated static libraries, which are named
with the pattern `lib${foo}.a`:

* https://mesonbuild.com/FAQ.html#why-does-building-my-project-with-msvc-output-static-libraries-called-libfooa

Note that this was previously attempted by

* commit be848a71b0 (MSVC: Teach find_library to consider the 'libfoo.a'
                     naming convention, 2022-09-19, v3.25.0-rc1~111^2)

but was reverted by

* commit 955d6245c1 (MSVC: Revert "Teach find_library to consider the
                     'libfoo.a' naming convention", 2022-11-28, v3.25.1~6^2)

due to problems finding GNU ABI libraries in PATH-derived prefixes.
Since then,

* commit 0a81110b84 (find_(library|file|path): Drop PATH-derived search
                     prefixes, 2023-09-14, v3.28.0-rc1~91^2)

removed the problematic search paths, so we can restore this change.

Fixes: #23975

1 files changed, 7 insertions, 0 deletions

diff --git a/Help/release/dev/find_library-msvc-libfoo.a.rst b/Help/release/dev/find_library-msvc-libfoo.a.rst
new file mode 100644
index 0000000..23ba226
--- /dev/null
+++ b/Help/release/dev/find_library-msvc-libfoo.a.rst
@@ -0,0 +1,7 @@
+find_library-msvc-libfoo.a
+--------------------------
+
+* On Windows, when targeting the MSVC ABI, the :command:`find_library` command
+  now accepts ``.a`` file names after first considering ``.lib``.  This is
+  symmetric with existing behavior when targeting the GNU ABI, in which the
+  command accepts ``.lib`` file names after first considering ``.a``.