[Win32] mingw-w64 ports of gcc-13 will break 32-bit builds of perl

[sisyphus]

Description
With mingw-w64 ports of gcc-13, 32-bit versions of setjmp.h will no longer look at whether USE_NO_MINGW_SETJMP_TWO_ARGS is defined.
This change means that dist/threads/threads.xs won't compile using gcc-13. (No such issue with gcc-12 and earlier.)
Martin Storsjo (who is a member of the mingw-w64 development team) has generously provided me with the following patch to the perl source that (verified) will fix this problem:

---
 XSUB.h                  | 14 ++++++++++++++
 dist/threads/threads.xs | 17 -----------------
 2 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/XSUB.h b/XSUB.h
index 82cd0dc777..b7f92abc5f 100644
--- a/XSUB.h
+++ b/XSUB.h
@@ -504,7 +504,14 @@ Rethrows a previously caught exception.  See L<perlguts/"Exception Handling">.
 #    undef fgetpos
 #    undef ioctl
 #    undef getlogin
+
+/* Don't undefine/redefine setjmp on Windows; PerlProc_setjmp gets redirected
+ * back to plain setjmp in the end, but then we've lost the system header's
+ * definition of it. Just keep the system headers versions of setjmp intact. */
+#ifndef _WIN32
 #    undef setjmp
+#endif
+
 #    undef getc
 #    undef ungetc
 #    undef fileno
@@ -609,8 +616,15 @@ Rethrows a previously caught exception.  See L<perlguts/"Exception Handling">.
 #    define sleep		PerlProc_sleep
 #    define times		PerlProc_times
 #    define wait		PerlProc_wait
+
+/* Don't undefine/redefine setjmp on Windows; PerlProc_setjmp gets redirected
+ * back to plain setjmp in the end, but then we've lost the system header's
+ * definition of it. Just keep the system headers versions of setjmp intact. */
+#ifndef _WIN32
 #    define setjmp		PerlProc_setjmp
 #    define longjmp		PerlProc_longjmp
+#endif
+
 #    define signal		PerlProc_signal
 #    define getpid		PerlProc_getpid
 #    define gettimeofday	PerlProc_gettimeofday
diff --git a/dist/threads/threads.xs b/dist/threads/threads.xs
index 25fec167aa..1a403af2f6 100644
--- a/dist/threads/threads.xs
+++ b/dist/threads/threads.xs
@@ -1,24 +1,7 @@
 #define PERL_NO_GET_CONTEXT
-/* Workaround for mingw 32-bit compiler by mingw-w64.sf.net - has to come before any #include.
- * It also defines USE_NO_MINGW_SETJMP_TWO_ARGS for the mingw.org 32-bit compilers ... but
- * that's ok as that compiler makes no use of that symbol anyway */
-#if defined(WIN32) && defined(__MINGW32__) && !defined(__MINGW64__)
-#  define USE_NO_MINGW_SETJMP_TWO_ARGS 1
-#endif
 #include "EXTERN.h"
 #include "perl.h"
 #include "XSUB.h"
-/* Workaround for XSUB.h bug under WIN32 */
-#ifdef WIN32
-#  undef setjmp
-#  if defined(USE_NO_MINGW_SETJMP_TWO_ARGS) || (!defined(__BORLANDC__) && !defined(__MINGW64__))
-#    define setjmp(x) _setjmp(x)
-#  endif
-#  if defined(__MINGW64__)
-#    include <intrin.h>
-#    define setjmp(x) _setjmpex((x), mingw_getsp())
-#  endif
-#endif
 #define NEED_PL_signals
 #define NEED_sv_2pv_flags
 #include "ppport.h"
---

Things to note:

1. It's simple, elegant, and removes a heap of crud;
2. It doesn't distinguish between different windows compilers;
3. It doesn't even distinguish between different versions of gcc.

Applying this patch to perl-5.37.10, I've checked that perl still builds and tests fine for both 32-bit and 64-bit versions of both gcc-12.2.0 and gcc-13.0.1.
I've also checked that this patch (applied to 5.37.10) works fine with 32-bit and 64-bit VS-2022 compilers. (With the 32-bit VS-2022 I built both MSWin32-x86-multi-thread and MSWin32-x86-multi-thread-64int.)

To me, it looks great, and I'll be applying this patch to the perls that I build henceforth.
But I haven't (eg) tested it using any gcc versions older than 12.2.0.

Anyway .... I'm putting the patch up here as something that people might like to test and/or comment upon.

If you think there's a better way to deal with the impending issue with gcc-13, now is a good time to speak up.

Snapshots of mingw-w64 ports of the gcc-13.0.1 toolchain can be downloaded from:
https://gcc-mcf.lhmouse.com/
or
https://winlibs.com

EDIT: fixed typo

Cheers,
Rob

[sisyphus]

#21142 LGTM.
Apply those changes, in preference to the patches provided here.

Cheers,
Rob