Remove use of deprecated ustat interface in glibc 2.28:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85835

Taken from upstream:

https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=260684

diff --git a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
index 858bb2184505..de18e56d11cf 100644
--- a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
+++ b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
@@ -157,7 +157,6 @@ typedef struct user_fpregs elf_fpregset_t;
 # include <sys/procfs.h>
 #endif
 #include <sys/user.h>
-#include <sys/ustat.h>
 #include <linux/cyclades.h>
 #include <linux/if_eql.h>
 #include <linux/if_plip.h>
@@ -250,7 +249,19 @@ namespace __sanitizer {
 #endif // SANITIZER_LINUX || SANITIZER_FREEBSD
 
 #if SANITIZER_LINUX && !SANITIZER_ANDROID
-  unsigned struct_ustat_sz = sizeof(struct ustat);
+  // Use pre-computed size of struct ustat to avoid <sys/ustat.h> which
+  // has been removed from glibc 2.28.
+#if defined(__aarch64__) || defined(__s390x__) || defined (__mips64) \
+  || defined(__powerpc64__) || defined(__arch64__) || defined(__sparcv9) \
+  || defined(__x86_64__)
+#define SIZEOF_STRUCT_USTAT 32
+#elif defined(__arm__) || defined(__i386__) || defined(__mips__) \
+  || defined(__powerpc__) || defined(__s390__)
+#define SIZEOF_STRUCT_USTAT 20
+#else
+#error Unknown size of struct ustat
+#endif
+  unsigned struct_ustat_sz = SIZEOF_STRUCT_USTAT;
   unsigned struct_rlimit64_sz = sizeof(struct rlimit64);
   unsigned struct_statvfs64_sz = sizeof(struct statvfs64);
 #endif // SANITIZER_LINUX && !SANITIZER_ANDROID
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<div class='path'>path: <a href='/guix/log/?id=0a5b060be1e8966abc45e4782df83447510a90b4'>root</a>/<a href='/guix/log/tests?id=0a5b060be1e8966abc45e4782df83447510a90b4'>tests</a>/<a href='/guix/log/tests/cve-sample.json?id=0a5b060be1e8966abc45e4782df83447510a90b4'>cve-sample.json</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/cve-sample.json?id=0a5b060be1e8966abc45e4782df83447510a90b4&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-12-21 17:47:35 +0100'>2020-12-21</span></td><td><a href='/guix/commit/tests/cve-sample.json?id=9608f4003dedd8dfe99327c15668ca1a43ebd93b'>tests: Fix malformed JSON.</a><span class='msg-avail'>...<span class='msg-tooltip'>Guile-JSON 4.3.2 would parse in spite of these typos, but 4.4.1 is
stricter.

* tests/swh.scm (%directory-entries): Add missing comma.
* tests/cve-sample.json: Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>