[PATCH v2 6/6] t4124: fix test for non-compliance diff

POSIX's diff(1) requires output in normal diff format.
However, busybox's diff's output is written in unified format.

POSIX requires no option for normal-diff format.

A hint in test-lib-functions::test_cmp said `diff -u` isn't available
everywhere.

Workaround this problem by assuming `diff(1)` output is unified
if we couldn't make anything from normal-diff format.

Signed-off-by: Đoàn Trần Công Danh <redacted>
---
 t/t4124-apply-ws-rule.sh | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/t/t4124-apply-ws-rule.sh b/t/t4124-apply-ws-rule.sh
index 971a5a7512..2a54ce96b5 100755
--- a/t/t4124-apply-ws-rule.sh
+++ b/t/t4124-apply-ws-rule.sh

@@ -52,6 +52,12 @@ test_fix () {
 
 	# find touched lines
 	$DIFF file target | sed -n -e "s/^> //p" >fixed
+	if ! test -s fixed; then
+		$DIFF file target |
+		grep '^+' |
+		grep -v '^+++' |
+		sed -e "s/+//" >fixed
+	fi
 
 	# the changed lines are all expected to change
 	fixed_cnt=$(wc -l <fixed)

-- 
2.26.0.rc2.310.g2932bb562d