Fix OpenBSD build (#700)

git-svn-id: http://svn.osgeo.org/geos/branches/3.4@3997 5242fede-7e19-0410-aef8-94bd7d2200fb
Note OpenBSD build fix in the NEWS file

git-svn-id: http://svn.osgeo.org/geos/branches/3.4@3998 5242fede-7e19-0410-aef8-94bd7d2200fb