fix(build/embed): include all Emacs C sources and related files in th…

…e Emacs.app bundle

Changelog files from the `src` directory are however excluded. They're
6.7MB, span 1985 to 2015, and are not very relevant for inclusion within
the Emacs.app bundle.

Resolves #40

build-emacs-for-macos

@@ -409,6 +409,10 @@ class Build
 
     patches.each { |patch| apply_patch(patch, target) }
 
+    # Keep a copy of src after patches have been applied. This will be used to
+    # embed C sources into the output Emacs.app bundle.
+    cmd('cp', '-a', File.join(target, 'src'), File.join(target, 'src.orig'))
+
     target
   end
 
@@ -1211,16 +1215,18 @@ class CSourcesEmbedder < AbstractEmbedder
   def embed
     info 'Bundling C source files into Emacs.app for documentation purposes...'
 
+    orig_src_dir = File.join(source_dir, 'src.orig')
     src_dir = File.join(source_dir, 'src')
     target_dir = File.join(resources_dir, 'src')
-    debug "Copying *.c and *.h files from '#{src_dir}' " \
-          "to: #{relative_path(target_dir)}"
 
-    Dir[File.join(src_dir, '**', '*.{c,h}')].each do |f|
-      rel = f[src_dir.size + 1..-1]
-      target = File.join(target_dir, rel)
-      FileUtils.mkdir_p(File.dirname(target))
-      cmd('cp', '-pRL', f, target)
+    debug "Copying Emacs C sources to #{relative_app_path(target_dir)}"
+
+    if File.exist?(orig_src_dir)
+      copy_sources(orig_src_dir, target_dir)
+    else
+      copy_sources(
+        src_dir, target_dir, File.join('**', '*.{awk,c,cc,h,in,m,mk}')
+      )
     end
 
     if File.exist?(site_start_el_file) &&
@@ -1235,6 +1241,18 @@ class CSourcesEmbedder < AbstractEmbedder
 
   private
 
+  def copy_sources(src_dir, target_dir, pattern = File.join('**', '*'))
+    Dir[File.join(src_dir, pattern)].each do |f|
+      next if File.directory?(f) ||
+              File.basename(f).downcase.start_with?('changelog')
+
+      rel = relative_path(src_dir, f)
+      target = File.join(target_dir, rel)
+      FileUtils.mkdir_p(File.dirname(target))
+      run_cmd('cp', '-pRL', f, target)
+    end
+  end
+
   def site_start_el_file
     @site_start_el_file ||= File.join(resources_dir, 'lisp', 'site-start.el')
   end
@@ -1260,10 +1278,9 @@ class LibEmbedder < AbstractEmbedder
     binary ||= bin
 
     FileUtils.cd(File.dirname(app)) do
-      rel_path = Pathname.new(lib_dir).relative_path_from(
-        Pathname.new(File.dirname(binary))
-      ).to_s
-      rpath = File.join('@executable_path', rel_path)
+      rpath = File.join(
+        '@executable_path', relative_path(File.dirname(binary), lib_dir)
+      )
 
       copy, relink = build_bundle_plan(binary)