linker script ASSERT

[Nick Clifton]

Hi Nathan,

> the linker's documentation implies that one can use ASSERT (expr, msg)
> as a command, but the grammar only allows it in an expression.  This
> patch makes it usable as a command.  Also, it wasn't being recognised
> by exp_init_os, thus assertions about otherwise uncreated sections
> would crash.

Have you tested this patch ?  If so how ?

Please could you also create a linker testsuite file to check the new
functionality so that we can make sure that this feature does not get
forgotten in the future.

Cheers
        Nick