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
@@ -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/lib/sanitizer_common/sanitizer_platform_limits_posix.h b/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
@@ -188,17 +188,16 @@ namespace __sanitizer {
     unsigned __seq;
     u64 __unused1;
     u64 __unused2;
-#elif defined(__mips__) || defined(__aarch64__)
-    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;
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<div class='path'>path: <a href='/guix/log/?id=f15800946d688398ec09a86b23d01ebef91800e0'>root</a>/<a href='/guix/log/gnu?id=f15800946d688398ec09a86b23d01ebef91800e0'>gnu</a>/<a href='/guix/log/gnu/packages?id=f15800946d688398ec09a86b23d01ebef91800e0'>packages</a>/<a href='/guix/log/gnu/packages/scanner.scm?id=f15800946d688398ec09a86b23d01ebef91800e0'>scanner.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/scanner.scm?id=f15800946d688398ec09a86b23d01ebef91800e0&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2018-07-25 11:52:59 +0300'>2018-07-25</span></td><td><a href='/guix/commit/gnu/packages/scanner.scm?id=8e1895964fd10fbf5f19ad39ca080f684a6246d6'>gnu: Add hplip-minimal.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/cups.scm (hplip-minimal): New variable.
* gnu/packages/scanner.scm (sane-backends)[inputs]: Replace hplip with
hplip-minimal.
* doc/guix.texi (Printing Services): Change example code to use
hplip-minimal in place of hplip. Add note explaining when use hplip.
</span></span></td><td>Efraim Flashner</td></tr>