New Features in macOS Big Sur 11 Universal Apps Beta 4
Starting with Xcode 12 beta 4, the toolchain will now automatically sign your executables whenever you build from Xcode, or use command-line utilities such as clang(1) or ld(1) . This new mechanism generates signatures directly at link time, and doesn’t cover any resource other than the executable. As a result, it’s expected to be faster than a traditional codesign(1) invocation. If you use a custom workflow involving tools that modify a binary after linking (e.g. strip or install_name_tool ) you might need to manually call codesign(1) as an additional build phase to properly ad-hoc sign your binary.New in macOS 11 on Apple silicon Mac computers, and starting in the next macOS Big Sur 11 beta, the operating system will enforce that any executable must be signed with a valid signature before it’s allowed to run. There isn’t a specific identity requirement for this signature: a simple ad-hoc signature issued locally is sufficient, which includes signatures which are now generated automatically by the linker. This new behavior doesn’t change the long-established policy that our users and developers can run arbitrary code on their Macs, and is designed to simplify the execution policies on Apple silicon Mac computers and enable the system to better detect code modifications.This new policy doesn’t apply to translated x86 binaries running under Rosetta, nor does it apply to macOS 11 running on Intel platforms. (51911409)
So the linker used with Xojo For MacOS may need to apply an ad-hoc signature, even for debug builds.
Please take the chance to add code signing options right into Xojo.