As a follow up to this, I ran into an issue where I couldn't get the tools kmod to compile properly because of a change i kernel 5.2.21 (the return type of the fault handler functions changed from 'int' to 'vm_fault_t' (which is an unsigned int)). Digging back through the kernel archives the changes started earlier than that but by the time I updated Manjaro it was at 5.2.21 so that's what I went with. If anyone's interested, I can post the steps to fix it so that it builds for kernel 5.2.21. It does require editing code and tar'ing/untar'ing archives as the guides posted above do.