Map type ddefs to symbols, check the global env
Map type ddefs to symbols, check the global env

This commit changes the s-exp primitive to lookup paths in the global
env--using the context env isn't sufficient for type/module definitions.

carp-lang/Carp,carp-lang/Carp,eriksvedang/Carp,carp-lang/Carp,eriksvedang/Carp