ospoll: Fix Solaris ports implementation to build on Solaris 11.4

Wrong version got committed, but wasn't noticed since it only builds
with meson, not autoconf.

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
(cherry picked from commit 0e8c0d2f)
3 jobs for solaris-fixes-1.20 in 6 minutes and 23 seconds (queued for 1 second)