dev-build.py: remove semi-broken CC/CFLAGS processing
dev-build.py: remove semi-broken CC/CFLAGS processing

It ignored the fact that we now sometimes compile a C file,
and I sometimes had trouble with it so I'd stopped using it in favor
of directly passing -DCMAKE_* anyway.

Lasercake/Lasercake,elidupree/Lasercake,idupree/Lasercake,Lasercake/Lasercake,elidupree/Lasercake,idupree/Lasercake,idupree/Lasercake,idupree/Lasercake,elidupree/Lasercake,elidupree/Lasercake,idupree/Lasercake,elidupree/Lasercake,elidupree/Lasercake,elidupree/Lasercake,Lasercake/Lasercake,Lasercake/Lasercake,idupree/Lasercake,Lasercake/Lasercake,idupree/Lasercake