Gmt module. Error reporting in GMT_Type template.

modules/gmt/modgmt_func.h

@@ -1037,14 +1037,16 @@ class Convert2Struct<struct gmt_font, ObjectList>
  }
 };
 
+
 // Template for generating GMTObject from ObjectList
 template<class Struct>
 const ObjectBase* GMT_Type(const ObjectList* input)
 {
  bool suc=true;
- Struct s=Convert2Struct<Struct,ObjectList>()(input,&suc);
+ std::string err;
+ Struct s=Convert2Struct<Struct,ObjectList>()(input,&suc,err);
  if(suc) return new ObjectGMTClass<Struct>(s);
- else return 0;
+ else return new ObjectError("GMT function",err);
 }
 
 // Shift position of layer