Add a script to upgrade vendor/re

vendor/update-re.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+
+version=1.7.1
+
+set -e -o pipefail
+
+TMP="$(mktemp -d)"
+trap "rm -rf $TMP" EXIT
+
+rm -rf re
+mkdir -p re/src
+
+(cd $TMP && opam source re.$version)
+
+SRC=$TMP/re.$version
+
+cp -v $SRC/LICENSE re
+
+for m in re re_automata re_cset re_fmt; do
+    for ext in ml mli; do
+        fn=$SRC/lib/$m.$ext
+        [[ -f $fn ]] && cp -v $fn re/src
+    done
+done
+
+git checkout re/src/jbuild
+git add -A .