Adjust libsanitizer to ABI change in glibc 2.31.

Adapted to 3.x from this upstream commit:
https://github.com/llvm/llvm-project/commit/947f9692440836dcb8d88b74b69dd379d85974ce

diff --git a/lib/sanitizer_common/sanitizer_platform_limits_posix.cc b/lib/sanitizer_common/sanitizer_platform_limits_posix.cc
--- a/lib/sanitizer_common/sanitizer_platform_limits_posix.cc
+++ b/lib/sanitizer_common/sanitizer_platform_limits_posix.cc
@@ -1139,8 +1139,9 @@ 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/lib/sanitizer_common/sanitizer_platform_limits_posix.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
--- a/lib/sanitizer_common/sanitizer_platform_limits_posix.h
+++ b/lib/sanitizer_common/sanitizer_platform_limits_posix.h
@@ -194,17 +194,16 @@ namespace __sanitizer {
     unsigned __seq;
     u64 __unused1;
     u64 __unused2;
-#elif defined(__mips__) || defined(__aarch64__) || defined(__s390x__)
-    unsigned int mode;
-    unsigned short __seq;
-    unsigned short __pad1;
-    unsigned long __unused1;
-    unsigned long __unused2;
+#elif defined(__sparc__)
+  unsigned mode;
+  unsigned short __pad2;
+  unsigned short __seq;
+  unsigned long long __unused1;
+  unsigned long long __unused2;
 #else
-    unsigned short mode;
-    unsigned short __pad1;
-    unsigned short __seq;
-    unsigned short __pad2;
+  unsigned int mode;
+  unsigned short __seq;
+  unsigned short __pad2;
 #if defined(__x86_64__) && !defined(_LP64)
     u64 __unused1;
     u64 __unused2;
th: <a href='/guix/log/?id=4b28553e73cd00b7288272615a5105caf31ee692'>root</a>/<a href='/guix/log/tests?id=4b28553e73cd00b7288272615a5105caf31ee692'>tests</a>/<a href='/guix/log/tests/channels.scm?id=4b28553e73cd00b7288272615a5105caf31ee692'>channels.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/tests/channels.scm?id=4b28553e73cd00b7288272615a5105caf31ee692&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-09-18 19:37:45 +0200'>2021-09-18</span></td><td><a href='/guix/commit/tests/channels.scm?id=778c1fb4eabbb48c05f6c7555c89466d5249ebce'>channels: 'channel-news-entry-commit' correctly resolves annotated tags.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-10-12 18:23:47 +0200'>2020-10-12</span></td><td><a href='/guix/commit/tests/channels.scm?id=d3162b98a824a32ce955de18b9b891fbc4342d44'>tests: Add missing copyright line.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-10-12 11:28:56 +0200'>2020-10-12</span></td><td><a href='/guix/commit/tests/channels.scm?id=6c46e477eb50c6ee7c9b7c8199bdfb3708dc32b5'>channels: Address test failure.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-10-12 00:30:14 -0400'>2020-10-12</span></td><td><a href='/guix/commit/tests/channels.scm?id=875c01f82dc5f2c4ca82952ea88b3240fbe8bede'>tests: Mark the channel-instances-&gt;manifest as expected to fail.</a><span class='msg-avail'>...</span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2020-07-25 19:11:37 +0200'>2020-07-25</span></td><td><a href='/guix/commit/tests/channels.scm?id=d51bfe242fbe6f3f8f71d723e8fe0c7bbe711ba1'>Use 'formatted-message' instead of '&amp;message' where appropriate.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-07-25 19:11:36 +0200'>2020-07-25</span></td><td><a href='/guix/commit/tests/channels.scm?id=a5e2fc73760a2ae023f2e56bdbf8025971f90e64'>utils: Move &lt;location&gt; and '&amp;error-location' to (guix diagnostics).</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-07-01 23:34:51 +0200'>2020-07-01</span></td><td><a href='/guix/commit/tests/channels.scm?id=d774c7b1218a3cc20079b19812da119f9ed26b54'>channels: Dependencies listed in '.guix-channel' can have an introduction.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-07-01 23:34:51 +0200'>2020-07-01</span></td><td><a href='/guix/commit/tests/channels.scm?id=884df776408caa137456e91ba0f5fd71524cf6c3'>channels: Properly diagnose test failure.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-07-01 23:34:51 +0200'>2020-07-01</span></td><td><a href='/guix/commit/tests/channels.scm?id=8b7d982e6ae090eb5b3938db14a8eb2e2c3a1419'>channels: Make channel introductions public.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-06-28 23:26:53 +0200'>2020-06-28</span></td><td><a href='/guix/commit/tests/channels.scm?id=ead5c46147ebf352ad4804d52a766dcf105eda4f'>channels: Error out when the 'guix' channel lacks an introduction.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-06-25 01:20:31 +0200'>2020-06-25</span></td><td><a href='/guix/commit/tests/channels.scm?id=a18d02def9862dfb9b7a5e3d5aa3b541b066d198'>channels: Fix test for introductory commit signer.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>