VHDL String Compare and FPGA Family Determination

there is no way to use different libraries depending on any string.

You can use generics to control the instatiation of different components depending on device family.

There is no way of auto-collecting the device family. You have to set this yourself via a constant. You might be able to pick it up from Quartus via TCL and modify the constant/generic - but my TCL isnt very good.

As for string compare, you can just use an equals (remember its case sensitive):

cyclone_gen : if family = "CYCLONE" generate
...
end generate cyclone_gen;