gnu: ocaml-4.09: Fix signal handling with newer glibc.

* gnu/packages/patches/ocaml-4.09-dynamically-allocate-signal-stack.patch:
New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/ocaml.scm (ocaml-4.09): Use it.

gnu/local.mk

@@ -1580,6 +1580,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/ocaml-dose3-dont-make-printconf.patch	\
   %D%/packages/patches/ocaml-dose3-Install-mli-cmx-etc.patch	\
   %D%/packages/patches/ocaml-multiple-definitions.patch		\
+  %D%/packages/patches/ocaml-4.09-dynamically-allocate-signal-stack.patch	\
   %D%/packages/patches/ocaml-4.09-multiple-definitions.patch	\
   %D%/packages/patches/omake-fix-non-determinism.patch	\
   %D%/packages/patches/oneko-remove-nonfree-characters.patch	\

gnu/packages/ocaml.scm

@@ -316,7 +316,9 @@ functional, imperative and object-oriented styles of programming.")
                     "http://caml.inria.fr/pub/distrib/ocaml-"
                     (version-major+minor version)
                     "/ocaml-" version ".tar.xz"))
-              (patches (search-patches "ocaml-4.09-multiple-definitions.patch"))
+              (patches (search-patches
+                         "ocaml-4.09-multiple-definitions.patch"
+                         "ocaml-4.09-dynamically-allocate-signal-stack.patch"))
               (sha256
                (base32
                 "1v3z5ar326f3hzvpfljg4xj8b9lmbrl53fn57yih1bkbx3gr3yzj"))))

gnu/packages/patches/ocaml-4.09-dynamically-allocate-signal-stack.patch

@@ -0,0 +1,52 @@
+From 95f5016955e519c392c746e38e0c9460f2c1aa0c Mon Sep 17 00:00:00 2001
+From: Julien Lepiller <julien@lepiller.eu>
+Date: Sun, 19 Feb 2023 09:58:57 +0100
+Subject: [PATCH] Dynamically allocate the alternate signal stack.
+
+This patch is a backport of https://github.com/ocaml/ocaml/pull/10266.
+---
+ runtime/signals_nat.c | 19 +++++++++++--------
+ 1 file changed, 11 insertions(+), 8 deletions(-)
+
+diff --git a/runtime/signals_nat.c b/runtime/signals_nat.c
+index 29a5f49..a193fc2 100644
+--- a/runtime/signals_nat.c
++++ b/runtime/signals_nat.c
+@@ -182,7 +182,6 @@ DECLARE_SIGNAL_HANDLER(trap_handler)
+ #ifdef HAS_STACK_OVERFLOW_DETECTION
+ 
+ static char * system_stack_top;
+-static char sig_alt_stack[SIGSTKSZ];
+ 
+ #if defined(SYS_linux)
+ /* PR#4746: recent Linux kernels with support for stack randomization
+@@ -274,15 +273,19 @@ void caml_init_signals(void)
+ #ifdef HAS_STACK_OVERFLOW_DETECTION
+   {
+     stack_t stk;
+-    struct sigaction act;
+-    stk.ss_sp = sig_alt_stack;
++    stk.ss_sp = malloc(SIGSTKSZ);
+     stk.ss_size = SIGSTKSZ;
+     stk.ss_flags = 0;
+-    SET_SIGACT(act, segv_handler);
+-    act.sa_flags |= SA_ONSTACK | SA_NODEFER;
+-    sigemptyset(&act.sa_mask);
+-    system_stack_top = (char *) &act;
+-    if (sigaltstack(&stk, NULL) == 0) { sigaction(SIGSEGV, &act, NULL); }
++    if (stk.ss_sp != NULL) {
++      if (sigaltstack(&stk, NULL) != -1) {
++        struct sigaction act;
++        SET_SIGACT(act, segv_handler);
++        act.sa_flags |= SA_ONSTACK | SA_NODEFER;
++        sigemptyset(&act.sa_mask);
++        system_stack_top = (char *) &act;
++        sigaction(SIGSEGV, &act, NULL);
++      }
++    }
+   }
+ #endif
+ }
+-- 
+2.38.1
+