[hurd,commited] hurd: Avoid PLTs for __mach_thread_self and __mach_reply_port

[Joseph Myers]

I'm now seeing build failures for i686-gnu, of the form:

/scratch/jmyers/glibc-bot/build/glibcs/i686-gnu/glibc/htl/libpthread_pic.a(pt-barrier-wait.os): In function `pthread_barrier_wait':
/scratch/jmyers/glibc-bot/build/glibcs/i686-gnu/glibc-src/htl/../sysdeps/htl/pt-barrier-wait.c:59: undefined reference to `__mach_thread_self'

-- 
Joseph S. Myers
joseph@codesourcery.com