Vendor the external cookbooks

Knife-Zero doesn't include Berkshelf support, so vendoring everything in
the repo is convenient again

cookbooks/mingw/files/default/custom-upgrade.sh

@@ -0,0 +1,23 @@
+declare -r CRITICAL_PACKAGES="bash pacman msys2-runtime"
+declare -r OPTIONAL_PACKAGES="msys2-runtime-devel"
+
+# set pacman command if not already defined
+PACMAN=${PACMAN:-pacman}
+# save full path to command as PATH may change when sourcing /etc/profile
+PACMAN_PATH=$(type -P $PACMAN)
+
+run_pacman() {
+	local cmd
+	cmd=("$PACMAN_PATH" "$@")
+	"${cmd[@]}"
+}
+
+if ! run_pacman -Sy; then
+  exit 1
+fi
+
+run_pacman -Qu ${CRITICAL_PACKAGES}
+
+if ! run_pacman -S --noconfirm --needed ${CRITICAL_PACKAGES} ${OPTIONAL_PACKAGES}; then
+  exit 1
+fi