jabberd -- denial-of-service vulnerability

José Antonio Calvo discovered a bug in the Jabber 1.x server.
According to Matthias Wimmer:

Without this patch, it is possible to remotly crash
jabberd14, if there is access to one of the following types
of network sockets:

Socket accepting client connections
Socket accepting connections from other servers
Socket connecting to an other Jabber server
Socket accepting connections from server components
Socket connecting to server components

This is any socket on which the jabberd server parses
XML!
The problem existed in the included expat XML parser code.
This patch removes the included expat code from jabberd14
and links jabberd against an installed version of expat.