version.c: support RUBY_ENGINE_VERSION

* version.c (Init_version): the version of the engine or
  interpreter.  [Fix GH-858]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50186 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Wed Apr  8 17:45:02 2015  Shannon Skipper  <shannonskipper@gmail.com>
+
+	* version.c (Init_version): the version of the engine or
+	  interpreter.  [Fix GH-858]
+
 Wed Apr  8 16:15:30 2015  Kenta Murata  <mrkn@cookpad.com>
 
 	* bigdecimal: conform to ruby's license.  [ruby-core:68466] [Bug #10952]

version.c

@@ -38,10 +38,11 @@ VALUE ruby_engine_name = Qnil;
 void
 Init_version(void)
 {
+    VALUE v = MKSTR(version);
     /*
      * The running version of ruby
      */
-    rb_define_global_const("RUBY_VERSION", MKSTR(version));
+    rb_define_global_const("RUBY_VERSION", v);
     /*
      * The date this ruby was released
      */
@@ -71,6 +72,10 @@ Init_version(void)
      * The engine or interpreter this ruby uses.
      */
     rb_define_global_const("RUBY_ENGINE", ruby_engine_name = MKSTR(engine));
+    /*
+     * The version of the engine or interpreter this ruby uses.
+     */
+    rb_define_global_const("RUBY_ENGINE_VERSION", v);
 }
 
 /*! Prints the version information of the CRuby interpreter to stdout. */