From c169c2bf9299035b40f42c809c2de1e8ccbf36d8 Mon Sep 17 00:00:00 2001
From: Stephen Heumann <stephenheumann@gmail.com>
Date: Sun, 13 Feb 2022 18:10:45 -0600
Subject: [PATCH] Fully prohibit redefinition of predefined macros.

Code like the following was previously being allowed:

#define __STDC__ /* no tokens */
---
 Scanner.pas | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Scanner.pas b/Scanner.pas
index bab212a..c3adff2 100644
--- a/Scanner.pas
+++ b/Scanner.pas
@@ -2552,6 +2552,8 @@ var
       mPtr^.algorithm := 0;
       if IsDefined(mPtr^.name) then begin
          mf := macroFound;
+         if mf^.readOnly then
+            goto 3;
          if mf^.parameters = mPtr^.parameters then begin
             tk1 := mf^.tokens;
             tk2 := mPtr^.tokens;