Revert "meson.build: Disable -fzero-call-used-regs on OpenBSD"

This reverts commit 2d6d995709482cc8b6a76dbb5334a28001a14a9a.

OpenBSD 7.7 fixed the problem with the -fzero-call-used-regs on OpenBSD,
see https://github.com/openbsd/src/commit/03eca72d1e030b7a542cd6aec1 for
the fix there.

Suggested-by: Brad Smith <brad@comstyle.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20250508144120.163009-6-thuth@redhat.com>
1 file changed