thread.c (mutex_alloc): remove needless volatile

Allocation functions do not do anything non-obvious to the
compiler, so there's no reason for volatile here.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51271 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,7 @@
+Thu Jul 16 19:12:30 2015  Eric Wong  <e@80x24.org>
+
+	* thread.c (mutex_alloc): remove needless volatile
+
 Thu Jul 16 22:05:29 2015  Koichi Sasada  <ko1@atdot.net>
 
 	* vm_core.h: constify rb_iseq_t::parent_iseq.

thread.c

@@ -4189,7 +4189,7 @@ rb_obj_is_mutex(VALUE obj)
 static VALUE
 mutex_alloc(VALUE klass)
 {
-    VALUE volatile obj;
+    VALUE obj;
     rb_mutex_t *mutex;
 
     obj = TypedData_Make_Struct(klass, rb_mutex_t, &mutex_data_type, mutex);