https://www.illumos.org/issues/16561
https://lore.kernel.org/git/ZkeJx97qdLoaC2H-@telcontar/

--- git-2.45.1/t/t4150-am.sh.orig
+++ git-2.45.1/t/t4150-am.sh
@@ -1218,7 +1218,7 @@
 	test_path_is_missing .git/rebase-apply &&
 	git show empty-commit --format="%B" >expected &&
 	git show HEAD --format="%B" >actual &&
-	grep -f actual expected &&
+	ggrep -f actual expected &&
 	grep "Creating an empty commit: empty commit" output
 '
 
@@ -1244,7 +1244,7 @@
 	test_path_is_missing .git/rebase-apply &&
 	git show empty-commit --format="%B" >expected &&
 	git show HEAD --format="%B" >actual &&
-	grep -f actual expected
+	ggrep -f actual expected
 '
 
 test_expect_success 'create an non-empty commit when the index IS changed though "--allow-empty" is given' '
@@ -1255,7 +1255,7 @@
 	git am --allow-empty &&
 	git show empty-commit --format="%B" >expected &&
 	git show HEAD --format="%B" >actual &&
-	grep -f actual expected &&
+	ggrep -f actual expected &&
 	git diff HEAD^..HEAD --name-only
 '