hooks:pre-commit: Check for absolute links too

I don't really want any absolute links here.

meta/git/hooks/pre-commit

@@ -42,15 +42,22 @@ if ! git diff-index --check --cached $against --; then
 	die
 fi
 
-# Check that added symlinks are not broken
+# Check that added symlinks are neither absolute nor broken
 git diff --staged --name-only --diff-filter=AR $against \
 | {
-	broken=0
+	abort=0
 	while read -r line; do
-		if [ -h "$line" ] && [ ! -e "$line" ]; then
-			broken=1
+		[ -h "$line" ] || continue
+
+		target="$(readlink "$line")"
+		if [ "${target:0:1}" = "/" ]; then
+			abort=1
+			printf "%s\n" "$line: Absolute symlink" >&2
+		fi
+		if [ ! -e "$line" ]; then
+			abort=1
 			printf "%s\n" "$line: Broken symlink" >&2
 		fi
 	done
-	(( ! broken )) || die
+	(( ! abort )) || die
 }