feature #914: update rubygems if version older than 1.3.6

share/install_gems/install_gems

@@ -90,6 +90,62 @@ class String
     end
 end
 
+def good_gem_version?
+    v=`gem --version`.strip
+    version=Gem::Version.new(v)
+    version>=Gem::Version.new('1.3.6')
+end
+
+def install_rubygems
+    if !good_gem_version?
+        puts(<<-EOT.unindent())
+            The rubygems version installed is too old to install some required
+            libraries. We are about to update your rubygems version. If you
+            want to do this by other means cancel this installation with
+            CTRL+C now.
+
+            Press ENTER to continue...
+
+EOT
+
+        STDIN.readline
+
+        `gem install rubygems-update --version '= 1.3.6'`
+
+        if $?.ecxitstatus!=0
+            puts "Error updating rubygems"
+            exit(-1)
+        end
+
+        update_rubygems_path=[
+            '/usr/bin/update_rubygems',
+            '/var/lib/gems/1.8/bin/update_rubygems',
+            '/var/lib/gems/1.9/bin/update_rubygems'
+        ]
+
+        installed=false
+
+        update_rubygems_path.each do |path|
+            if File.exist?(path)
+                `#{path}`
+
+                if $?.exitstatus!=0
+                    puts "Error executing update_rubygems"
+                    exit(-1)
+                end
+
+                installed=true
+                break
+             end
+        end
+
+        if !installed
+            puts "Could not find update_rubygems executable"
+            exit(-1)
+        end
+    end
+end
+
 def installed_gems
     text=`gem list --no-versions --no-details`
     if $?.exitstatus!=0
@@ -331,6 +387,7 @@ try_library :mkmf, <<-EOT.unindent
         * Install the ruby development package for your distro
 EOT
 
+install_rubygems
 
 command=''
 params=ARGV