From 088717ccec9d5311fc22340729df37fc83900e69 Mon Sep 17 00:00:00 2001
From: nhmall <nhmall@nethack.org>
Date: Mon, 18 Dec 2023 11:52:16 -0500
Subject: [PATCH] do not use the NONNULLxxx macros with djgpp [cross]compiler

For now, this will prevent the NONNULLxxx arguments from being
defined under a djgpp compiler or crosscompiler.

paxed reported a segfault under msdos:

nethack.exe
Exiting due to signal SIGSEGV
Page fault at eip=000c3f8c, error=0004
eax=00000000 ebx=00000000 ecx=00000000 edx=0000000f esi=00000000 edi=00000001
ebp=00589988 esp=00589970 program=C:\NH370\NETHACK.EXE
cs: sel=00a7  base=00400000  limit=0063ffff
ds: sel=00af  base=00400000  limit=0063ffff
es: sel=00af  base=00400000  limit=0063ffff
fs: sel=008f  base=00001a20  limit=0000ffff
gs: sel=00bf  base=00000000  limit=0010ffff
ss: sel=00af  base=00400000  limit=0063ffff
App stack: [00589ba8..00389ba8]  Exceptn stack: [00389af4..00387bb4]

Call frame traceback EIPs:
  0x000c3f8c _read_config_file+19
  0x0017619f _initoptions_finish+577
  0x00176371 _initoptions+157
  0x0025cec4 _pcmain+365
  0x0025d8d9 _main+41

He was able to 'git bisect' to the macro definitions change,
and confirmed that the segfault no longer occurs after this commit.

There may be further investigation on this later.
---
 include/tradstdc.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/tradstdc.h b/include/tradstdc.h
index 6bb60b5bf..128a9dca9 100644
--- a/include/tradstdc.h
+++ b/include/tradstdc.h
@@ -373,6 +373,10 @@ typedef genericptr genericptr_t; /* (void *) or (char *) */
 #define DO_DEFINE_NONNULLS
 #endif
 
+#if defined(__DJGPP__) && defined(DO_DEFINE_NONNULLS)
+#undef DO_DEFINE_NONNULLS
+#endif
+
 #if defined(DO_DEFINE_NONNULLS) && !defined(NONNULLS_DEFINED)
 #define NONNULL __attribute__((returns_nonnull))
 #define NONNULLPTRS __attribute__((nonnull))