diff --git a/tool/rbinstall.rb b/tool/rbinstall.rb
index 6ee63855bf..26abfe33b2 100755
--- a/tool/rbinstall.rb
+++ b/tool/rbinstall.rb
@@ -354,7 +354,7 @@ install?(:local, :arch, :bin, :'bin-arch') do
   end
 end
 
-install?(:local, :arch, :lib) do
+install?(:local, :arch, :lib, :'lib-arch') do
   prepare "base libraries", libdir
 
   install lib, libdir, :mode => $prog_mode, :strip => $strip unless lib == arc
@@ -398,7 +398,7 @@ install?(:ext, :arch, :'ext-arch') do
     end
   end
 end
-install?(:ext, :arch, :hdr, :'arch-hdr') do
+install?(:ext, :arch, :hdr, :'arch-hdr', :'hdr-arch') do
   prepare "extension headers", archhdrdir
   install_recursive("#{$extout}/include/#{CONFIG['arch']}", archhdrdir, :glob => "*.h", :mode => $data_mode)
 end
@@ -408,7 +408,7 @@ install?(:ext, :comm, :'ext-comm') do
   prepare "extension scripts", sitelibdir
   prepare "extension scripts", vendorlibdir
 end
-install?(:ext, :comm, :hdr, :'comm-hdr') do
+install?(:ext, :comm, :hdr, :'comm-hdr', :'hdr-comm') do
   hdrdir = rubyhdrdir + "/ruby"
   prepare "extension headers", hdrdir
   install_recursive("#{$extout}/include/ruby", hdrdir, :glob => "*.h", :mode => $data_mode)
@@ -749,7 +749,14 @@ end
 
 # :startdoc:
 
-install?(:ext, :comm, :gem) do
+install?(:ext, :comm, :gem, :'default-gem', :'default-gem-comm') do
+  install_default_gem('lib', srcdir)
+end
+install?(:ext, :arch, :gem, :'default-gem', :'default-gem-arch') do
+  install_default_gem('ext', srcdir)
+end
+
+def install_default_gem(dir, srcdir)
   gem_dir = Gem.default_dir
   directories = Gem.ensure_gem_subdirectories(gem_dir, :mode => $dir_mode)
   prepare "default gems", gem_dir, directories
@@ -758,7 +765,7 @@ install?(:ext, :comm, :gem) do
   default_spec_dir = "#{spec_dir}/default"
   makedirs(default_spec_dir)
 
-  gems = Dir.glob(srcdir+"/{lib,ext}/**/*.gemspec").map {|src|
+  gems = Dir.glob("#{srcdir}/#{dir}/**/*.gemspec").map {|src|
     spec = Gem::Specification.load(src) || raise("invalid spec in #{src}")
     file_collector = RbInstall::Specs::FileCollector.new(src)
     files = file_collector.collect
@@ -787,7 +794,7 @@ install?(:ext, :comm, :gem) do
   end
 end
 
-install?(:ext, :comm, :gem) do
+install?(:ext, :comm, :gem, :'bundled-gem') do
   gem_dir = Gem.default_dir
   directories = Gem.ensure_gem_subdirectories(gem_dir, :mode => $dir_mode)
   prepare "bundle gems", gem_dir, directories