Beast CMakeLists is no longer compatible with cmake 3.8

[anarthal]

The CMakeLists.txt refactor performed in commit 75e4528 seem to have broken compatibility with CMake 3.8. See this MySQL build: https://drone.cpp.al/boostorg/mysql/955/3/3

The problem seems to be that target_sources(... PRIVATE) is not supported for INTERFACE targets in CMake 3.8.

This problem only happens in develop.

[ashtum]

Thanks for reporting this! Did you check if target_sources is the only issue?

[anarthal]

It's the only problem reported by the build. It may be covering other issues. If you want to test locally, you can use the ghcr.io/anarthal-containers/build-cmake3_8 Docker image (it's an Ubuntu with cmake 3.8)

[ashtum]

Yes, it seems that's the only issue.