RFA: Add dg-require-int-sized-pointers to testsuite

[Richard Sandiford]

Janis Johnson <janis187@us.ibm.com> writes:
> Richard S., I'm not sure what the outcome was on xfailing the tests
> that expect sizeof(int)==sizeof(char*).  You can either add a new
> check_ proc for that and add it to is-effective-target, or else use
> { dg-require-effective-target ilp32 }.

rth approved the latter.  I was just about to check it in, but I see
Eric Botcazou has since posted the same patch and had it approved a
second time ;) so hopefully it's now sorted once and for all.

Richard