Commit: CI: install gnudiff and enable `Test_diffmode` on macos-14 runner again (#14056)

[Christian Brabandt]

CI: install gnudiff and enable `Test_diffmode` on macos-14 runner again (#14056)

Commit: https://github.com/vim/vim/commit/72a1f45e9324f7e3b668b25cb18d2499df94720e
Author: Linda_pp <rh...@users.noreply.github.com>
Date: Tue Feb 20 04:55:55 2024 +0900

CI: install gnudiff and enable `Test_diffmode` on macos-14 runner again (https://github.com/vim/vim/issues/14056)

Signed-off-by: rhysd <lin9...@yahoo.co.jp>
Signed-off-by: Christian Brabandt <c...@256bit.org>

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 677630baa..a641ef563 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -373,6 +373,11 @@ jobs:
"${SRCDIR}"/vim -u NONE -i NONE --not-a-term -esNX -V1 -S ci/if_ver-1.vim -c quit
"${SRCDIR}"/vim -u NONE -i NONE --not-a-term -esNX -V1 -S ci/if_ver-2.vim -c quit

+ - name: Install packages for testing
+ run: |
+ # Apple diff is broken. Use GNU diff instead. See #14032.
+ brew install diffutils
+
- name: Test
timeout-minutes: 20
run: |