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 196eb3b3c64..b588e07e5ab 100644
--- a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
+++ b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
@@ -928,7 +928,11 @@ 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 !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
 CHECK_SIZE_AND_OFFSET(ipc_perm, __seq);
 
 CHECK_TYPE_SIZE(shmid_ds);
diff --git a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h
index aec950454b3..6d94fc65c28 100644
--- a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h
+++ b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h
@@ -154,20 +154,13 @@ namespace __sanitizer {
     u64 __unused1;
     u64 __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)
alue='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=00d1ccaf1275df3b90198f3a4a52aaf9a16cac0e'>root</a>/<a href='/guix/log/gnu?id=00d1ccaf1275df3b90198f3a4a52aaf9a16cac0e'>gnu</a>/<a href='/guix/log/gnu/packages?id=00d1ccaf1275df3b90198f3a4a52aaf9a16cac0e'>packages</a>/<a href='/guix/log/gnu/packages/libunwind.scm?id=00d1ccaf1275df3b90198f3a4a52aaf9a16cac0e'>libunwind.scm</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/gnu/packages/libunwind.scm?id=00d1ccaf1275df3b90198f3a4a52aaf9a16cac0e&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-01-20 10:51:54 +0200'>2021-01-20</span></td><td><a href='/guix/commit/gnu/packages/libunwind.scm?id=b2477b5c4f8fc7ddd8ed6275351f0a2075e576b0'>gnu: libunwind: Update to 1.5.0.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/libunwind.scm (libunwind): Update to 1.5.0.

Signed-off-by: Efraim Flashner &lt;efraim@flashner.co.il&gt;
</span></span></td><td>Vincent Legoll</td></tr>