Xcode: Restore support for CMAKE_OSX_ARCHITECTURES=$(ARCHS_STANDARD) Skip the `CMAKE_OSX_ARCHITECTURES` validation added by commit db409e5e68 (APPLE: Check if compilers respect CMAKE_OSX_ARCHITECTURES, 2024-05-04, v3.30.0-rc1~15^2) if the value contains a placeholder, since we do not know the real value. Fixes: #26128