add attributes for enumerated values in ilang

- information also useful for strongly-typed enums (not implemented)
- resolves enum values in ilang part of #1594
- still need to output enums to VCD (or better yet FST) files

frontends/ast/ast.cc

@@ -1222,6 +1222,7 @@ void AST::process(RTLIL::Design *design, AstNode *ast, bool dump_ast1, bool dump
 		}
 		else {
 			// must be global definition
+			(*it)->simplify(false, false, false, 1, -1, false, false); //process enum/other declarations
 			design->verilog_globals.push_back((*it)->clone());
 		}
 	}