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)