autogenerated tag for origin/for-next

Remove several implicit function declarations

During configure, several ioctl checks omit the corresponding include
and a pwritev2 check uses the wrong feature test macro.
This commit fixes the same.

Signed-off-by: Arjun Shankar <arjun@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>