Fix up add_method on the metaclass to be more inline with the HOW API…

… proposed by smop.

src/classes/ClassHOW.pir

@@ -481,6 +481,19 @@ Accessor for hidden property.
     .return ($P0)
 .end
 
+
+=item add_method
+
+=cut
+
+.sub 'add_method' :method
+    .param pmc obj
+    .param string name
+    .param pmc meth
+    $P0 = getattribute self, 'parrotclass'
+    addmethod $P0, name, meth
+.end
+
 =back
 
 =cut

src/parrot/Protoobject.pir

@@ -134,14 +134,14 @@ Indicate that objects in the class are mutable or immutable.
 .sub '!IMMUTABLE' :method
     $P0 = get_root_global [.RAKUDO_HLL ; 'Int'], 'Scalar'
     $P1 = self.'HOW'()
-    $P1.'add_method'('Scalar', $P0, 'to'=>self)
+    $P1.'add_method'(self, 'Scalar', $P0)
 .end
 
 .namespace ['P6protoobject']
 .sub '!MUTABLE' :method
     $P0 = get_root_global [.RAKUDO_HLL ; 'Perl6Object'], 'Scalar'
     $P1 = self.'HOW'()
-    $P1.'add_method'('Scalar', $P0, 'to'=>self)
+    $P1.'add_method'(self, 'Scalar', $P0)
 .end
 
 =back