Makefile template: Use a set instead of a list, where relevant.
Makefile template: Use a set instead of a list, where relevant.

As far as I can see, the insertion order of this collection doesn't matter.

agacek/camkes-tool,smaccm/camkes-tool,smaccm/camkes-tool,smaccm/camkes-tool,agacek/camkes-tool,smaccm/camkes-tool,agacek/camkes-tool