THRIFT-388. Create a "ONEWAY" message type that is an alias for "CALL"

Pave the way for a new message type for oneway function calls.
For now, just define the constant in all languages and make
server implementations treat it the same way as a normal call.
Only C++ and Erlang currently check the message type (on the
server side).

There is a little bit of redundancy in the Erlang code, but
the alternative is a bit gross, and this split-up will be
necessary eventually when we start handling one-way calls
differently.


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@761389 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/php/src/Thrift.php b/lib/php/src/Thrift.php
index dd1e0d7..ef6ab8a 100644
--- a/lib/php/src/Thrift.php
+++ b/lib/php/src/Thrift.php
@@ -51,6 +51,7 @@
   const CALL  = 1;
   const REPLY = 2;
   const EXCEPTION = 3;
+  const ONEWAY = 4;
 }
 
 /**