It looks like currently include directories are only pulled from the INCLUDE_DIRECTORIES property of a target. One would expect that INTERFACE_INCLUDE_DIRECTORIES and possibly INTERFACE_SYSTEM_INCLUDE_DIRECTORIES should be added to the include path as well.
Added INTERFACE_INCLUDE_DIRECTORIES to includes, Not sure about the INTERFACE_SYSTEM_INCLUDE_DIRECTORIES, but if someone comes in with a case that needs it it can be added
It looks like currently include directories are only pulled from the INCLUDE_DIRECTORIES property of a target. One would expect that INTERFACE_INCLUDE_DIRECTORIES and possibly INTERFACE_SYSTEM_INCLUDE_DIRECTORIES should be added to the include path as well.