ensure-not-yet-deployed: support the ucrt64 pseudo architecture

In conjunction with the new `ucrt64` pseudo architecture in the
`build-and-deploy` workflow, teach this script that for UCRT64 builds
the MINGW package prefix is `mingw-w64-ucrt-x86_64` (not the literal
`mingw-w64-ucrt64`), and that the resulting packages are deployed
into the `x86_64` subdirectory of the Pacman repository, alongside
the MINGW64 packages.

The latter is so that the existing `git-for-windows-x86_64.db`
database can keep referencing both flavors during the MINGW64 ->
UCRT64 migration; the new `git-for-windows-ucrt64.db` database
introduced in git-for-windows/pacman-repo#4
lives in the same `x86_64` branch of `pacman-repo` for exactly that
reason.

Assisted-by: Opus 4.7
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

update-scripts/ensure-not-yet-deployed.sh

@@ -10,12 +10,11 @@ architecture=
 while case "$1" in
 --architecture=*)
 	architecture=${1#*=}
-	if test aarch64 = "$architecture"
-	then
-		MINGW_PACKAGE_PREFIX=mingw-w64-clang-aarch64
-	else
-		MINGW_PACKAGE_PREFIX=mingw-w64-$architecture
-	fi
+	case "$architecture" in
+	aarch64) MINGW_PACKAGE_PREFIX=mingw-w64-clang-aarch64;;
+	ucrt64)  MINGW_PACKAGE_PREFIX=mingw-w64-ucrt-x86_64;;
+	*)       MINGW_PACKAGE_PREFIX=mingw-w64-$architecture;;
+	esac
 	;;
 -*) die "Unhandled option: '$1'";;
 *) break;
@@ -27,6 +26,16 @@ die "Usage: $0 <directory-containing-PKGBUILD>"
 cd "$1" ||
 die "Could not switch to '$1'"
 
+# Some PKGBUILDs use $CARCH at top level (outside functions). Set it before
+# sourcing so that architecture-dependent logic (case statements, variable
+# assignments) works correctly even though we are not running under makepkg.
+case "$architecture" in
+aarch64)  CARCH=aarch64;;
+i686)     CARCH=i686;;
+*)        CARCH=x86_64;;
+esac &&
+export CARCH &&
+
 . ./PKGBUILD ||
 die "No/invalid PKGBUILD in '$1'?"
 
@@ -58,7 +67,7 @@ esac &&
 
 subdir="${architecture:-$arch}" &&
 case "$subdir" in
-any) subdir=x86_64;;
+any|ucrt64) subdir=x86_64;;
 esac &&
 
 case "$pkgname" in