make mingw fedora 39 use libgnurx if re2 is not available

[simsong]

I have no idea what performance will be like.

[root@b3d53215cc2e build]# yum search libgnurx
Last metadata expiration check: 0:27:57 ago on Mon Feb  5 13:49:41 2024.
=================================================== Name Matched: libgnurx ===================================================
mingw32-libgnurx.noarch : MinGW Regex library
mingw32-libgnurx-static.noarch : Static version of the MinGW Windows regular expression library
mingw64-libgnurx.noarch : MinGW Regex library
mingw64-libgnurx-static.noarch : Static version of the MinGW Windows regular expression library
[root@b3d53215cc2e build]#

Perhaps @jonstewart can recommend something else?