Disable -Wrestrict for two nptl/tst-attr3.c tests [committed]

[Florian Weimer]

On 12/18/2017 11:56 PM, Joseph Myers wrote:
> nptl/tst-attr3 fails to build with GCC mainline because of
> (deliberate) aliasing between the second (attributes) and fourth
> (argument to thread start routine) arguments to pthread_create.
> 
> Although both those arguments are restrict-qualified in POSIX,
> pthread_create does not actually dereference its fourth argument; it's
> an opaque pointer passed to the thread start routine.  Thus, the
> aliasing is actually valid in this case,

I think the restrict requirements extend to called functions as well, 
due to the way the execution of a block is defined in C11 (“an execution 
of [a block] B means that portion of the execution of the program that 
would correspond to the lifetime of an object with scalar type and 
automatic storage duration associated with B”).

The proper fix seems to be to remove the restrict qualifier from the 
last argument of pthread_create, considering that the thread start 
routine argument lacks the restrict qualifier, too.

Thanks,
Florian