Add external function identifier to the resolver

External function identifiers were not added to the resolver and thus
could not be resolved later.

gcc/rust/ChangeLog:

	* resolve/rust-toplevel-name-resolver-2.0.cc (TopLevel::visit): Add a
	visitor function override for external function identifiers.
	* resolve/rust-toplevel-name-resolver-2.0.h: Add function prototype.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

Author: P-E-P

gcc/rust/resolve/rust-toplevel-name-resolver-2.0.cc

@@ -302,6 +302,14 @@ TopLevel::visit (AST::Function &function)
   DefaultResolver::visit (function);
 }
 
+void
+TopLevel::visit (AST::ExternalFunctionItem &function)
+{
+  insert_or_error_out (function.get_identifier (), function, Namespace::Values);
+
+  DefaultResolver::visit (function);
+}
+
 void
 TopLevel::visit (AST::BlockExpr &expr)
 {

gcc/rust/resolve/rust-toplevel-name-resolver-2.0.h

@@ -87,6 +87,7 @@ class TopLevel : public DefaultResolver
   void visit (AST::Module &module) override;
   void visit (AST::MacroRulesDefinition &macro) override;
   void visit (AST::Function &function) override;
+  void visit (AST::ExternalFunctionItem &function) override;
   void visit (AST::BlockExpr &expr) override;
   void visit (AST::StaticItem &static_item) override;
   void visit (AST::TraitItemFunc &item) override;