with variations in EINTR behaviour, but the optimisation of using the
BSD version where the SYSV version isn't needed is insignificant.
This patch therefore simplifies the code by making there be just one
version, a more paranoid (about EOF when errno is already EINTR)
version of the SYSV code. Since the BSD/SYSV defines are mainly used
to control whether BSD timers are used, this helps where BSD timers
but SYSV EINTR handling are wanted.
Patch supplied in PR 8091 by Joseph Myers <jsm28@cam.ac.uk>