die_with_status: use "printf '%s\n'", not "echo"

Some implementations of 'echo' (e.g. dash's built-in) interpret
backslash sequences in their arguments.

This triggered at least one bug: the error message of "rebase -i" was
turning \t in commit messages into actual tabulations. There may be
others.

Using "printf '%s\n'" instead avoids this bad behavior, and is the form
used by the "say" function.

Noticed-by: David Kastrup <dak@gnu.org>
Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-sh-setup.sh

@@ -53,7 +53,7 @@ die () {
 die_with_status () {
 	status=$1
 	shift
-	echo >&2 "$*"
+	printf >&2 '%s\n' "$*"
 	exit "$status"
 }
 

t/t3404-rebase-interactive.sh

@@ -976,4 +976,17 @@ test_expect_success 'rebase -i with --strategy and -X' '
 	test $(cat file1) = Z
 '
 
+test_expect_success 'rebase -i error on commits with \ in message' '
+	current_head=$(git rev-parse HEAD)
+	test_when_finished "git rebase --abort; git reset --hard $current_head; rm -f error" &&
+	test_commit TO-REMOVE will-conflict old-content &&
+	test_commit "\temp" will-conflict new-content dummy &&
+	(
+	EDITOR=true &&
+	export EDITOR &&
+	test_must_fail git rebase -i HEAD^ --onto HEAD^^ 2>error
+	) &&
+	test_expect_code 1 grep  "	emp" error
+'
+
 test_done