io_pgetevents() will not change the signal mask. Mark it const
to make it clear and to reduce the need for casts in user code.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Avi Kivity <avi@scylladb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>