git-extra(i686): work around a libunistring version problem of gnupg

As of yesterday's big MSYS2 i686 sync, there is no longer an
`msys-unistring-2.dll` but an `msys-unistring-5.dll`.

However, gnupg (e.g. `dirmngr.exe`, via `msys-gnutls-30.dll`) depends on
the former file to be present.

Since the full i686 variant of Git for Windows is on its way out (we'll
be dropping the installer/portable Git builds for i686 after one last
full i686 release with Git for Windows v2.48.1, and MinGit does not
include gnupg), it isn't worth fretting too much about this; Simply
copying the latter to the former seems to work just fine.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

git-extra/git-extra.install.in

@@ -263,6 +263,13 @@ test -d "$TMPDIR" || test ! -d "$TMP" || {\
 	# Work around /etc/xml/catalog being updated using the MINGW version of xmlcatalog
 	! grep -q '"[CD]:/' /etc/xml/catalog ||
 	sed -i -e 's|"[CD]:/[^"]*/usr/|"/usr/|g' /etc/xml/catalog
+
+	# Work around an outdated i686 gnupg/gnutls build that depends on a hence-updated libunistring
+	if test i686 = $arch -a ! -e /usr/bin/msys-unistring-2.dll -a -e /usr/bin/msys-unistring-5.dll &&
+		grep msys-unistring-2 /usr/bin/msys-gnutls-30.dll 2>&1 >/dev/null
+	then
+		cp /usr/bin/msys-unistring-5.dll /usr/bin/msys-unistring-2.dll
+	fi
 }
 
 post_upgrade () {