Implement a primitive failsafe mechanism for protecting against
linking inconsistent object files.  The idea is that if object files
which were compiled in the wrong order (non-dependency order) or
compiled in different ways (eg. profiled vs. non-profiled) are linked
together, a link error will result.

This is achieved by adding the module version and the way to the
module init label.  For example, previously the init label for a
module Foo was named

	__stginit_Foo

now it is named

	__stginit_Foo_<version>_<way>

where <version> is the module version of Foo (same as the version in
the interface file), and <way> is the current way (or empty).

We also have to have a way to refer to the old plain init label, for
using as the argument to shutdownHaskell() in a program using foreign
exports.  So the old label now points to a jump instruction which
transfers control to the new init code.