Removing usage of git - not everyone grabs the gem using it.

ruby/google-protobuf.gemspec

@@ -8,11 +8,11 @@ Gem::Specification.new do |s|
   s.authors     = ["Protobuf Authors"]
   s.email       = "protobuf@googlegroups.com"
   s.require_paths = ["lib"]
-  s.files       = `git ls-files -z`.split("\x0").find_all{|f| f =~ /lib\/.+\.rb/}
+  s.files       = Dir.glob('lib/**/*.rb')
   if RUBY_PLATFORM == "java"
     s.files     += ["lib/google/protobuf_java.jar"]
   else
-    s.files     += `git ls-files "*.c" "*.h" extconf.rb Makefile`.split
+    s.files     += Dir.glob('ext/**/*')
     s.extensions= ["ext/google/protobuf_c/extconf.rb"]
     s.add_development_dependency "rake-compiler-dock"
   end