[easybuild] Toolchains

[khostetl]

So say I am building openmpi and I use dummy and dummy as name and version,
then what toolchain is it defaulting to? I would have originally thought it
was gcc, but when I try to manually use GCC as the name and dummy as the
version, it fails saying "Dependencies not met. Cannot resolve ["GCC/dummy..."
and this is while using --robot.