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 069d8d557de..c49c28c6e07 100644
--- a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
+++ b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
@@ -1130,8 +1130,9 @@ CHECK_SIZE_AND_OFFSET(ipc_perm, cgid);
 #ifndef __GLIBC_PREREQ
 #define __GLIBC_PREREQ(x, y) 0
 #endif
-#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 304d04e3935..6dee89c97e1 100644
--- a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h
+++ b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h
@@ -207,20 +207,13 @@ 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)

path'>path: <a href='/guix/log/?id=3504e39a5d8661b02a026b6ab3b386e3f49eeeaf'>root</a>/<a href='/guix/log/gnu?id=3504e39a5d8661b02a026b6ab3b386e3f49eeeaf'>gnu</a>/<a href='/guix/log/gnu/packages?id=3504e39a5d8661b02a026b6ab3b386e3f49eeeaf'>packages</a>/<a href='/guix/log/gnu/packages/sawfish.scm?id=3504e39a5d8661b02a026b6ab3b386e3f49eeeaf'>sawfish.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/sawfish.scm?id=3504e39a5d8661b02a026b6ab3b386e3f49eeeaf&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-03-15 01:08:08 +0100'>2020-03-15</span></td><td><a href='/guix/commit/gnu/packages/sawfish.scm?id=131f0f853e5ea6c4effe18fbd1a4e68a6c78624d'>gnu: librep: Update home page.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/sawfish.scm (librep)[home-page]: Follow (HTTPS)
redirection.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2020-03-15 01:08:07 +0100'>2020-03-15</span></td><td><a href='/guix/commit/gnu/packages/sawfish.scm?id=416d098a0e496935d851db472a6d891eb6bb2bad'>gnu: librep: Don't use NAME in source URI.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/sawfish.scm (librep)[source]: Hard-code NAME.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2019-06-27 12:22:04 +0530'>2019-06-27</span></td><td><a href='/guix/commit/gnu/packages/sawfish.scm?id=4ffed734198863105c564f16a30075cd2f76c1ee'>gnu: rep-gtk: Update to 0.90.8.3.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/sawfish.scm (rep-gtk): Update to 0.90.8.3.
[source]: Use HTTPS URI.
[arguments]: Add remove-autogen phase.
[native-inputs]: Add autoconf, automake and libtool.
[home-page]: Update URI.
</span></span></td><td>Arun Isaac</td></tr>
<tr><td><span title='2019-06-27 12:21:09 +0530'>2019-06-27</span></td><td><a href='/guix/commit/gnu/packages/sawfish.scm?id=edccf761e3d1fa384befb5a1cee95cc11eee09d9'>gnu: sawfish: Update to 1.12.0.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/sawfish.scm (sawfish): Update to 1.12.0.
[source]: Use HTTPS URI.
[home-page]: Update URI.

Signed-off-by: Arun Isaac &lt;arunisaac@systemreboot.net&gt;
</span></span></td><td>Benjamin Slade</td></tr>