Configure dmg builds to use newer APFS/LZFSE formats for non-legacy build

Use newer formats for creating the DMG file for distributing MacVim.
APFS has been supported fully since macOS 10.13, and from testing it
extracts faster than HFS+.

LZFSE (ULFO format) is newer than zlib/DEFLATE (UDZO format) and also
decompresses faster as well from testing. Note that there is a newer
compression scheme using LZMA (ULMO format) but it is only supported in
10.15+ which is too high for us as non-legacy builds need to target
10.13+. Also, from testing, the newer LZMA yields smaller files, but
takes more time to decompress than LZFSE.

Also, keeping using the old formats (HFS+/zlib) for legacy builds since
they need to work on 10.9, which don't support the newer formats.

Author: ychin

.github/workflows/ci-macvim.yaml

@@ -312,7 +312,11 @@ jobs:
         run: |
           # Use the --skip-jenkins flag to skip the prettify osascript calls which could fail due to permission issues in
           # CI environment.
-          make -C src macvim-dmg CREATEDMG_FLAGS=--skip-jenkins
+          if ${{ matrix.legacy == true }}; then
+            make -C src macvim-dmg-legacy CREATEDMG_FLAGS=--skip-jenkins
+          else
+            make -C src macvim-dmg CREATEDMG_FLAGS=--skip-jenkins
+          fi
 
           if ${{ matrix.publish_postfix != '' }}; then
             mv src/MacVim/build/Release/MacVim.dmg src/MacVim/build/Release/MacVim${{ matrix.publish_postfix }}.dmg

src/Makefile

@@ -3633,18 +3633,28 @@ DMGDIR = MacVim/build/dmg
 DMGFILE = MacVim.dmg
 ENTITLEMENTS = MacVim/MacVim.entitlements
 
+# APFS is supported in 10.13+, ULFO (LZFSE compression) in 10.11+.
+DMGFILESYSTEM = APFS
+DMGFORMAT = ULFO
+
 macvim: $(VIMTARGET)
 	xcodebuild -project MacVim/MacVim.xcodeproj $(XCODEFLAGS)
 
 macvim-signed:
 	MacVim/scripts/sign-developer-id $(RELEASEDIR)/MacVim.app $(ENTITLEMENTS)
 
+macvim-dmg-legacy: DMGFILESYSTEM = HFS+
+macvim-dmg-legacy: DMGFORMAT = UDZO
+macvim-dmg-legacy: macvim-dmg
+
 macvim-dmg:
 	rm -rf $(DMGDIR)
 	mkdir -p $(DMGDIR)
 	cp -a $(RELEASEDIR)/MacVim.app $(DMGDIR)/
 	rm -rf $(RELEASEDIR)/$(DMGFILE)
 	MacVim/create-dmg/create-dmg \
+		--filesystem "$(DMGFILESYSTEM)" \
+		--format "$(DMGFORMAT)" \
 		--volname "MacVim" \
 		--volicon MacVim/icons/MacVim.icns \
 		--background MacVim/dmg/background.png \