Update xcodeproj version, generate a compatible one for Xcode 8+

.github/workflows/ci-macvim.yaml

@@ -56,7 +56,7 @@ jobs:
           # Oldest version of Xcode supported on GitHub Action to test source code backwards compatibility
           - os: macos-11
             xcode: '11.7'
-            extra: [vimtags]
+            extra: [vimtags, check-xcodeproj-compat]
 
           # Older version of Xcode, and used to publish legacy builds (for macOS 10.9 - 10.12)
           - os: macos-12
@@ -300,6 +300,16 @@ jobs:
           make -C runtime/doc vimtags VIMEXE=../../${VIM_BIN}
           git diff --exit-code -- runtime/doc/tags
 
+      - name: Check Xcode project compatibility version
+        if: contains(matrix.extra, 'check-xcodeproj-compat')
+        run: |
+          # Confirm that the compatibility version of xcodeproj is correct and not outdated.
+          rm -rf src/MacVim/MacVim_xcode8.xcodeproj
+          make -C src macvim-xcodeproj-compat
+          if ! git diff --exit-code -- src/MacVim/MacVim_xcode8.xcodeproj; then
+            echo 'MacVim_xcode8.xcodeproj is outdated. Run "make -C src macvim-xcodeproj-compat" to re-generate it.'; false
+          fi
+
       - name: Build test binaries
         run: |
           # Build the unit test binaries first. With link-time-optimization they take some time to link. Running them

.gitignore

@@ -97,11 +97,11 @@ src/kword_test
 # From MacVim
 .*.swp
 .DS_Store
-src/MacVim/MacVim.xcodeproj/*.mode1
-src/MacVim/MacVim.xcodeproj/*.mode1v3
-src/MacVim/MacVim.xcodeproj/*.pbxuser
-src/MacVim/MacVim.xcodeproj/project.xcworkspace
-src/MacVim/MacVim.xcodeproj/xcuserdata
+src/MacVim/MacVim*.xcodeproj/*.mode1
+src/MacVim/MacVim*.xcodeproj/*.mode1v3
+src/MacVim/MacVim*.xcodeproj/*.pbxuser
+src/MacVim/MacVim*.xcodeproj/project.xcworkspace
+src/MacVim/MacVim*.xcodeproj/xcuserdata
 src/MacVim/icons/*.pyc
 src/MacVim/icons/*.ttf
 src/MacVim/icons/*.reg

src/MacVim/MacVim.xcodeproj/project.pbxproj

@@ -3,7 +3,7 @@
 	archiveVersion = 1;
 	classes = {
 	};
-	objectVersion = 47;
+	objectVersion = 54;
 	objects = {
 
 /* Begin PBXBuildFile section */