t4015 broken on pu

["Torsten Bögershausen" <tboegi@web.de>]

The new 4015 does not pass under Mac OS:

a) The seq command, does not exits (we can use printf)
b) One sed expression is not understood, sed exporst needed ;-)




 git diff
diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index b3c4fcc..f00d20b 100755
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -143,18 +143,18 @@ git diff --ignore-space-at-eol > out
 test_expect_success 'another test, with --ignore-space-at-eol' 'test_cmp expect out'
 
 test_expect_success 'ignore-blank-lines: only new lines' '
-       seq 5 >x &&
+       printf "1\n2\n3\n4\n5\n" >x &&
        git update-index x &&
-       seq 5 | sed "/3/i \\\\" >x &&
+       printf "1\n2\n3\n4\n5\n" | sed "/3/i \\\\" >x &&
        git diff --ignore-blank-lines >out &&
        printf "" >expect &&
        test_cmp out expect
 '
 
 test_expect_success 'ignore-blank-lines: only new lines with space' '
-       seq 5 >x &&
+       printf "1\n2\n3\n4\n5\n" >x &&
        git update-index x &&
-       seq 5 | sed "/3/i \ " >x &&
+       printf "1\n2\n3\n4\n5\n" | sed "/3/i \ " >x &&
        git diff -w --ignore-blank-lines >out &&
        printf "" >expect &&
        test_cmp out expect
@@ -162,7 +162,7 @@ test_expect_success 'ignore-blank-lines: only new lines with space' '
 
 
 test_expect_success 'ignore-blank-lines: with changes' '
-       seq 11 >x &&
+       printf "1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n" >x &&
        git update-index x &&
        cat <<-\EOF >x &&

================================
After that, TC 12 fails:
================================
ok 11 - another test, with --ignore-space-at-eol

expecting success: 
        printf "1\n2\n3\n4\n5\n" >x &&
        git update-index x &&
        printf "1\n2\n3\n4\n5\n" | sed "/3/i \\\\" >x &&
        git diff --ignore-blank-lines >out &&
        printf "" >expect &&
        test_cmp out expect

sed: 1: "/3/i \\": extra characters after \ at the end of i command
not ok 12 - ignore-blank-lines: only new lines