rbinstall.rb: reorder

* tool/rbinstall.rb: install default targets (:local, :ext) first,
  very time consuming tasks later.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43126 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

tool/rbinstall.rb

@@ -757,18 +757,23 @@ include FileUtils::NoWrite if $dryrun
 @fileutils_output = STDOUT
 @fileutils_label = ''
 
+all = $install.delete(:all)
 $install << :local << :ext if $install.empty?
-$install.each do |inst|
+installs = $install.map do |inst|
   if !(procs = $install_procs[inst]) || procs.empty?
     next warn("unknown install target - #{inst}")
   end
-  procs.each do |block|
-    dir = Dir.pwd
-    begin
-      block.call
-    ensure
-      Dir.chdir(dir)
-    end
+  procs
+end
+installs.flatten!
+installs.uniq!
+installs |= $install_procs[:all] if all
+installs.each do |block|
+  dir = Dir.pwd
+  begin
+    block.call
+  ensure
+    Dir.chdir(dir)
   end
 end