feat(patches/alpha-background): add experimental alpha-background patch (#129)

Resolves #111

Author: jimeh

README.md

@@ -131,7 +131,6 @@ Options:
     -j, --parallel COUNT             Compile using COUNT parallel processes (detected: 16)
         --git-sha SHA                Override detected git SHA of specified branch allowing builds of old commits
         --[no-]use-nix               Use Nix instead of Homebrew to find dependencies (default: enabled if IN_NIX_SHELL is set)
-        --[no-]xwidgets              Enable/disable XWidgets if supported (default: enabled)
         --[no-]tree-sitter           Enable/disable tree-sitter if supported (default: enabled)
         --[no-]native-comp           Enable/disable native-comp (default: enabled if supported)
         --optimize                   Shorthand for --native-march --native-mtune --fomit-frame-pointer (default: disabled)
@@ -142,10 +141,12 @@ Options:
         --[no-]relink-eln-files      Enable/disable re-linking shared libraries in bundled *.eln files (default: enabled)
         --[no-]rsvg                  Enable/disable SVG image support via librsvg (default: enabled)
         --[no-]dbus                  Enable/disable dbus support (default: enabled)
-        --no-titlebar                Apply no-titlebar patch (default: disabled)
-        --posix-spawn                Apply posix-spawn patch (deprecated)
-        --no-frame-refocus           Apply no-frame-refocus patch (default: disabled)
+        --[no-]alpha-background      Enable/disable experimental alpha-background patch when building Emacs 30.x - 31.x (default: disabled)
+        --no-frame-refocus           Apply no-frame-refocus patch when building Emacs 27.x - 31.x (default: disabled)
+        --no-titlebar                Apply no-titlebar patch when building Emacs 27.x - 28.x (default: disabled)
+        --[no-]xwidgets              Enable/disable XWidgets when building Emacs 27.x (default: disabled)
         --[no-]poll                  Apply poll patch (deprecated)
+        --posix-spawn                Apply posix-spawn patch (deprecated)
     -p, --patch=URL                  Specify a custom patch file or URL to apply to the Emacs source (can be used multiple times)
         --[no-]fd-setsize SIZE       Set an file descriptor (max open files) limit (default: 10000)
         --github-src-repo REPO       Specify a GitHub repo to download source tarballs from (default: emacs-mirror/emacs)

build-emacs-for-macos

@@ -218,7 +218,7 @@ class Build
     end
 
     tarball = download_tarball(meta[:sha])
-    @source_dir = extract_tarball(tarball, patches(options))
+    @source_dir = extract_tarball(tarball, build_patches)
 
     autogen
     detect_native_comp if options[:native_comp].nil?
@@ -1052,7 +1052,7 @@ class Build
       end
   end
 
-  def patches(opts = {})
+  def build_patches
     p = []
 
     # Enabled by default patches.
@@ -1129,14 +1129,30 @@ class Build
       }
     end
 
-    if opts[:xwidgets] && effective_version == 27
+    if options[:xwidgets] && effective_version == 27
       p << {
         url:
           'https://github.com/d12frosted/homebrew-emacs-plus/raw/master/' \
           "patches/emacs-#{effective_version}/xwidgets_webkit_in_cocoa.patch"
       }
     end
 
+    if options[:alpha_background]
+      if effective_version == 29
+        p << {
+          file: File.join(
+            __dir__, 'patches', 'emacs-29', 'ns-alpha-background.patch'
+          )
+        }
+      elsif (30..31).include?(effective_version)
+        p << {
+          url:
+          "https://github.com/emacs-mirror/emacs/compare/#{meta[:sha]}" \
+          '...jonrubens:emacs:ns-alpha-background.patch'
+        }
+      end
+    end
+
     # Custom patches.
     options[:patches].each do |patch_str|
       patch = {}
@@ -1940,12 +1956,6 @@ class CLIOptions
         '(default: enabled if IN_NIX_SHELL is set)'
       ) { |v| options[:use_nix] = v }
 
-      opts.on(
-        '--[no-]xwidgets',
-        'Enable/disable XWidgets if supported ' \
-        '(default: enabled)'
-      ) { |v| options[:xwidgets] = v }
-
       opts.on(
         '--[no-]tree-sitter',
         'Enable/disable tree-sitter if supported ' \
@@ -2010,23 +2020,37 @@ class CLIOptions
       ) { |v| options[:dbus] = v }
 
       opts.on(
-        '--no-titlebar',
-        'Apply no-titlebar patch (default: disabled)'
-      ) { options[:no_titlebar] = true }
-
-      opts.on('--posix-spawn', 'Apply posix-spawn patch (deprecated)') do
-        warn '==> WARN: posix-spawn patch is deprecated and has no effect.'
-      end
+        '--alpha-background',
+        'Apply experimental alpha-background patch when building Emacs ' \
+        '30.x - 31.x (default: disabled)'
+      ) { |v| options[:alpha_background] = v }
 
       opts.on(
         '--no-frame-refocus',
-        'Apply no-frame-refocus patch (default: disabled)'
+        'Apply no-frame-refocus patch when building Emacs 27.x - 31.x ' \
+        '(default: disabled)'
       ) { options[:no_frame_refocus] = true }
 
+      opts.on(
+        '--no-titlebar',
+        'Apply no-titlebar patch when building Emacs 27.x - 28.x ' \
+        '(default: disabled)'
+      ) { options[:no_titlebar] = true }
+
+      opts.on(
+        '--[no-]xwidgets',
+        'Enable/disable XWidgets when building Emacs 27.x ' \
+        '(default: disabled)'
+      ) { |v| options[:xwidgets] = v }
+
       opts.on('--[no-]poll', 'Apply poll patch (deprecated)') do
         warn '==> WARN: poll patch is deprecated and has no effect.'
       end
 
+      opts.on('--posix-spawn', 'Apply posix-spawn patch (deprecated)') do
+        warn '==> WARN: posix-spawn patch is deprecated and has no effect.'
+      end
+
       opts.on(
         '-p=URL', '--patch=URL',
         'Specify a custom patch file or URL to apply to the Emacs source ' \