Change to Proc.new to make Ruby 1.9 Happy

lib/mruby/source.rb

@@ -6,7 +6,7 @@ module MRuby
     ROOT = Pathname.new(File.expand_path('../../../',__FILE__))
 
     # Reads a constant defined at version.h
-    MRUBY_READ_VERSION_CONSTANT = -> (name) { ROOT.join('include','mruby','version.h').read.match(/^#define #{name} +"?([\w\. ]+)"?$/)[1] }
+    MRUBY_READ_VERSION_CONSTANT = Proc.new { |name| ROOT.join('include','mruby','version.h').read.match(/^#define #{name} +"?([\w\. ]+)"?$/)[1] }
 
     MRUBY_RUBY_VERSION = MRUBY_READ_VERSION_CONSTANT['MRUBY_RUBY_VERSION']
     MRUBY_RUBY_ENGINE = MRUBY_READ_VERSION_CONSTANT['MRUBY_RUBY_ENGINE']