Do ANF closed terms, don't ANF variable references
Do ANF closed terms, don't ANF variable references

Not ANF'ing all closed terms doesn't bring the program in the
desired normal form. What was desired is not to put global
variables in ANF (not bind globals in a let-binding). All
varaibles are expected to refer to closed terms, as ANF follows
the first-order transformation.

ggreif/clash-compiler,christiaanb/clash-compiler,christiaanb/clash-compiler,ggreif/clash-compiler