CMake Warning (dev) at build/_deps/autobahn-cpp-src/cmake/Includes/CMakeLists.txt:20 (if):
Policy CMP0054 is not set: Only interpret if() arguments as variables or
keywords when unquoted. Run "cmake --help-policy CMP0054" for policy
details. Use the cmake_policy command to set the policy and suppress this
warning.
Quoted variables like "MSVC" will no longer be dereferenced when the policy
is set to NEW. Since the policy is not set the OLD behavior will be used.
It should be fine to just opt into the new behaviour when it exists as autobahn-cpp doesn't seem to make use of it anyway. https://cmake.org/cmake/help/latest/policy/CMP0054.html
Another alternative for fixing this would be to bump the cmake_minimum_required from 2.8 to 3.1 (or higher). https://cmake.org/cmake/help/latest/manual/cmake-policies.7.html