[ruby/tsort] Use git magic signatures to exclude files

ruby/tsort@ab55dcb7f3

Author: nobu

lib/tsort.gemspec

@@ -20,8 +20,12 @@ Gem::Specification.new do |spec|
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = spec.homepage
 
-  spec.files         = Dir.chdir(File.expand_path('..', __FILE__)) do
-    `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
+  dir, gemspec = File.split(__FILE__)
+  excludes = %W[
+    :^/bin/ :^/test/ :^/spec/ :^/features/ :^/Gemfile :^/Rakefile
+  ]
+  spec.files = IO.popen(%w[git ls-files -z --] + excludes, chdir: dir) do |f|
+    f.read.split("\x0")
   end
   spec.bindir        = "exe"
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }