__ASSUME_COMPLETE_READV_WRITEV.
* sysdeps/unix/sysv/linux/readv.c: No need for userlevel fallback
with modern kernels.
* sysdeps/unix/sysv/linux/writev.c: Likewise.
* sysdeps/posix/readv.c: Since read is a cancellation point we have
to free a possible malloced buffer in case of cancellation.
* sysdeps/posix/writev.c: Likewise for write.
c2009-04-01 Ulrich Drepper <drepper@redhat.com>