patch 9.0.0668: CI on Mac M1 only uses clang

Problem:    CI on Mac M1 only uses clang
Solution:   Also run with gcc. (closes #11263)
diff --git a/.cirrus.yml b/.cirrus.yml
index a1f055b..f11c92c 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -27,12 +27,27 @@
     - sudo -u cirrus make test
 
 macos_task:
-  name: macOS m1
+  name: macOS (arm64 gcc)
   macos_instance:
     image: ghcr.io/cirruslabs/macos-ventura-xcode:latest
   timeout_in: 20m
   install_script:
-    - uname -a
+    - brew update
+    - brew install gettext libtool
+  build_script:
+    - NPROC=$(getconf _NPROCESSORS_ONLN)
+    - ./configure --with-features=${FEATURES}
+    - make -j${NPROC}
+  test_script:
+    - src/vim --version
+    - make test
+
+macos_task:
+  name: macOS (arm64 clang)
+  macos_instance:
+    image: ghcr.io/cirruslabs/macos-ventura-xcode:latest
+  timeout_in: 20m
+  install_script:
     - brew update
     - brew install gettext libtool
   build_script:
diff --git a/src/version.c b/src/version.c
index 0d3e911..b7bb569 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    668,
+/**/
     667,
 /**/
     666,