fcl-passrc: fixed parent of const external modifier

compiler/packages/fcl-passrc/src/pparser.pp

@@ -3866,7 +3866,7 @@ begin
             NextToken;
             if not (CurToken in [tkChar,tkString,tkIdentifier]) then
               ParseExcTokenError(TokenInfos[tkString]);
-            Result.ExportName:=DoParseExpression(Parent);
+            Result.ExportName:=DoParseExpression(Result);
             Result.IsConst:=true; // external const is readonly
             end
           else if CurToken=tkSemicolon then

compiler/packages/pastojs/tests/tcfiler.pas

@@ -1637,6 +1637,7 @@ begin
   '  s = ''abc'';', // string lit
   '  c: char = s[1];', // array params
   '  a: array[1..2] of longint = (3,4);', // anonymous array, range, array values
+  '  PI: Double; external name ''Math.PI'';',
   'resourcestring',
   '  rs = ''rs'';',
   'implementation']);