The runtime repository is missing a top level Makefile for building and (at least for now) selecting one of the 2 runtimes to be installed.

The Makefile installation step should also always create a symbolic link from kata-runtime to the runtime of choice binary name.

For example, in the cc-runtime case:

$ export KATA_RUNTIME=cc
$ make # Calls into make -C cc-runtime build-kata-system
$ make install # Calls into make -C cc-runtime install-kata-system and creates a link from kata-runtime to the cc binary