Fix assertion failure in libsanitizer when using glibc 2.31 and later.

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92154
https://reviews.llvm.org/D69104

Adapted from these upstream revision:

https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=277981
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=279653

diff --git a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
index 97eae3fc7bc..4089d4695e2 100644
--- a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
+++ b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
@@ -1145,8 +1145,9 @@ CHECK_SIZE_AND_OFFSET(ipc_perm, uid);
 CHECK_SIZE_AND_OFFSET(ipc_perm, gid);
 CHECK_SIZE_AND_OFFSET(ipc_perm, cuid);
 CHECK_SIZE_AND_OFFSET(ipc_perm, cgid);
-#if !defined(__aarch64__) || !SANITIZER_LINUX || __GLIBC_PREREQ (2, 21)
-/* On aarch64 glibc 2.20 and earlier provided incorrect mode field.  */
+#if !SANITIZER_LINUX || __GLIBC_PREREQ (2, 31)
+/* glibc 2.30 and earlier provided 16-bit mode field instead of 32-bit
+   on many architectures.  */
 CHECK_SIZE_AND_OFFSET(ipc_perm, mode);
 #endif
 
diff --git a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h
index c139322839a..7c3c2d866e5 100644
--- a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h
+++ b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h
@@ -211,20 +211,13 @@ namespace __sanitizer {
     unsigned long __unused1;
     unsigned long __unused2;
 #elif defined(__sparc__)
-# if defined(__arch64__)
     unsigned mode;
-    unsigned short __pad1;
-# else
-    unsigned short __pad1;
-    unsigned short mode;
     unsigned short __pad2;
-# endif
     unsigned short __seq;
     unsigned long long __unused1;
     unsigned long long __unused2;
 #else
-    unsigned short mode;
-    unsigned short __pad1;
+    unsigned int mode;
     unsigned short __seq;
     unsigned short __pad2;
 #if defined(__x86_64__) && !defined(_LP64)

guix/log/etc?id=b59632da27aec2e4333df647ff76f9830f97f431'>etc</a>/<a href='/guix/log/etc/git?id=b59632da27aec2e4333df647ff76f9830f97f431'>git</a>/<a href='/guix/log/etc/git/post-merge?id=b59632da27aec2e4333df647ff76f9830f97f431'>post-merge</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/etc/git/post-merge?id=b59632da27aec2e4333df647ff76f9830f97f431&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2024-05-25 16:23:56 +0200'>2024-05-25</span></td><td><a href='/guix/commit/etc/git/post-merge?id=73b3f941d7d911a1b2bb2bf77d37cb3a12ed4291'>maint: Suggest ‘guix git authenticate’ for initial authentication.</a><span class='msg-avail'>...<span class='msg-tooltip'>The previous recommendation, running ‘make authenticate’, was insecure
because it led users to run code from the very repository they want to
authenticate:

  https://lists.gnu.org/archive/html/guix-devel/2024-04/msg00252.html

* Makefile.am (commit_v1_0_0, channel_intro_commit)
(channel_intro_signer, GUIX_GIT_KEYRING, authenticate): Remove.
* Makefile.am (.git/hooks/%): New target, generalization of previous
‘.git/hooks/pre-push’ target.
(nodist_noinst_DATA): Add ‘.git/hooks/post-merge’.
* doc/contributing.texi (Building from Git): Suggest ‘guix git
authenticate’ instead of ‘make authenticate’.
* etc/git/post-merge: New file.
* etc/git/pre-push: Run ‘guix git authenticate’ instead of ‘make
authenticate’.

Reviewed-by: Maxim Cournoyer &lt;maxim.cournoyer@gmail.com&gt;
Reported-by: Skyler Ferris &lt;skyvine@protonmail.com&gt;
Change-Id: Ia415aa8375013d0dd095e891116f6ce841d93efd
</span></span></td><td>Ludovic Courtès</td></tr>