macOS: Avoid relying on sw_vers when cross-compiling from another OS We have a few code paths needed only to support builds hosted on macOS 10.4. Update the conditions to work when cross-compiling to macOS from another platform. This backports commit eb8facd396 (macOS: Avoid relying on sw_vers when cross-compiling from another OS, 2025-04-28, v4.1.0-rc1~260^2) to CMake 4.0. Fixes: #26814