fix bug when collecting compinfos for global types

a typedef will return True if its underlying type is a
struct, but it does not also proxy compinfo, so we need
to check for that case first, 'deref' (so to speak) the
typedef, and then we should be able to access the compinfo

This seems to have been triggered by a header with this type
definition:
```
typedef struct ___sigset_t __sigset_t;
```

Author: waskyo

chb/bctypes/BCFiles.py

@@ -34,7 +34,7 @@
 from chb.bctypes.BCDictionary import BCDictionary
 from chb.bctypes.BCEnumInfo import BCEnumInfo
 from chb.bctypes.BCFunctionDefinition import BCFunctionDefinition
-from chb.bctypes.BCTyp import BCTyp, BCTypComp
+from chb.bctypes.BCTyp import BCTyp, BCTypComp, BCTypNamed
 from chb.bctypes.BCTypeInfo import BCTypeInfo
 from chb.bctypes.BCVarInfo import BCVarInfo
 
@@ -81,6 +81,10 @@ def genumtags(self) -> List[BCEnumInfo]:
     def fsum_compinfos(self) -> List[BCCompInfo]:
         result: List[BCCompInfo] = []
         for typ in self.gtypes:
+            if typ.is_typedef:
+                typedef = cast("BCTypNamed", typ).typedef
+                if typedef:
+                    typ = typ = cast("BCTypeInfo", typedef).ttype
             if typ.is_struct:
                 compinfo = cast("BCTypComp", typ).compinfo
                 result.append(compinfo)