Update the cmake family to 3.9.6 (skip 3.9.5, the upstream
releases are coming quick and fast). Upstream changes are

• AUTOMOC options fixes (3.9.5)
• gcc_eh linking (3.9.6)

Thanks antoine@ for the exp-runs.

PR: 223436
Approved by: tcberner (mentor)
Differential Revision: https://reviews.freebsd.org/D12958