[cmake] Fix -Wunused-command-line-argument with clang

Summary: This especially happen for -fstack-clash-protection which is not detected as unused. See https://gitlab.kitware.com/cmake/cmake/-/issues/21998.

Test Plan: Run the guix osx build and check for no warning

Reviewers: #bitcoin_abc, tobias_ruck

Reviewed By: #bitcoin_abc, tobias_ruck

Subscribers: tobias_ruck

Differential Revision: https://reviews.bitcoinabc.org/D17277