[libitm] Link with -litm and -pthread

[Hans-Peter Nilsson]

On Sat, 11 Feb 2012, Eric Botcazou wrote:
> Hi,
>
> this completes the half-implemented linking scheme of libitm and makes it mimic
> that of libgomp entirely.  We need the -pthread thing on Solaris 8.

It broke all targets that don't implement threads and as such
don't support -pthread.  And you need to gate *all* tm-related
tests on something like check_effective_target_pthread.
I see regress-155 for cris-elf.

Can't you just limit adding -pthread to Solaris 8 or something?

brgds, H-P