Ajout hooks git de gestion de droits

contrib/git-hook-post-checkout

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+#!/bin/sh
+# Git pre-checkout hook restoring permissions and ownerships.
+mtree -u < .mtree

contrib/git-hook-pre-commit

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+#!/bin/sh
+# Git pre-commit hook storing permissions and ownerships.
+
+mtreeignore=$(mktemp --suffix mtree)
+
+mtree_exclude() {
+    echo .git
+    # Get ignored files from git https://stackoverflow.com/a/467053
+    find . -not -path './.git/*' | git check-ignore --stdin
+}
+
+# In case .mtree doens't exists yet, we still want it in the specification
+# to be generated.
+if [ -f .mtree ]; then
+   touch .mtree
+fi
+
+mtree_exclude > "$mtreeignore"
+trap 'rm --force "$mtreeignore"' EXIT
+
+mtree -x -c \
+    -p . \
+    -k uname,gname,mode \
+    -X "$mtreeignore" > .mtree
+
+git add .mtree