On various places (mostly waitpid() calls) this patch makes sure that if errno
== EINTR on return, then the syscall is endlessly retried.  It also defines a
simple generic way to do this.

Signed-off-by: <blaisorblade_spam@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>