getauxval() from glibc-compatibility did not work always correctly:

- it does not work after setenv(), and this breaks vsyscalls,
  like sched_getcpu() [1] (and BaseDaemon.cpp always set TZ if timezone
  is defined, which is true for CI [2]).

  [1]: https://bugzilla.redhat.com/show_bug.cgi?id=1163404
  [2]: ClickHouse#32928 (comment)

- another think that is definitely broken is LSan (Leak Sanitizer), it
  relies on worked getauxval() but it does not work if __environ is not
  initialized yet (there is even a commit about this).

  And because of, at least, one leak had been introduced [3]:

    [3]: ClickHouse#33840

Fix this by using /proc/self/auxv.

And let's see how many issues will LSan find...

I've verified this patch manually by printing AT_BASE and compared it
with output of LD_SHOW_AUXV.

Signed-off-by: Azat Khuzhin <[email protected]>

getauxval() from glibc-compatibility did not work always correctly:

- It does not work after setenv(), and this breaks vsyscalls,
  like sched_getcpu() [1] (and BaseDaemon.cpp always set TZ if timezone
  is defined, which is true for CI [2]).

  Also note, that fixing setenv() will not fix LSan,
  since the culprit is getauxval()

  [1]: https://bugzilla.redhat.com/show_bug.cgi?id=1163404
  [2]: ClickHouse#32928 (comment)

- Another think that is definitely broken is LSan (Leak Sanitizer), it
  relies on worked getauxval() but it does not work if __environ is not
  initialized yet (there is even a commit about this).

  And because of, at least, one leak had been introduced [3]:

    [3]: ClickHouse#33840

Fix this by using /proc/self/auxv with fallback to environ solution to
make it compatible with environment that does not allow reading from
auxv (or no procfs).

v2: add fallback to environ solution
v3: fix return value for __auxv_init_procfs()
Refs: ClickHouse#33957
Signed-off-by: Azat Khuzhin <[email protected]>

getauxval() from glibc-compatibility did not work always correctly:

- It does not work after setenv(), and this breaks vsyscalls,
  like sched_getcpu() [1] (and BaseDaemon.cpp always set TZ if timezone
  is defined, which is true for CI [2]).

  Also note, that fixing setenv() will not fix LSan,
  since the culprit is getauxval()

  [1]: https://bugzilla.redhat.com/show_bug.cgi?id=1163404
  [2]: ClickHouse#32928 (comment)

- Another think that is definitely broken is LSan (Leak Sanitizer), it
  relies on worked getauxval() but it does not work if __environ is not
  initialized yet (there is even a commit about this).

  And because of, at least, one leak had been introduced [3]:

    [3]: ClickHouse#33840

Fix this by using /proc/self/auxv with fallback to environ solution to
make it compatible with environment that does not allow reading from
auxv (or no procfs).

v2: add fallback to environ solution
v3: fix return value for __auxv_init_procfs()
(cherry picked from commit f187c34)
v4: more verbose message on errors, CI founds [1]:
    AUXV already has value (529267711)
    [1]: https://s3.amazonaws.com/clickhouse-test-reports/39103/2325f7e8442d1672ce5fb43b11039b6a8937e298/stress_test__memory__actions_.html
v5: break at AT_NULL
v6: ignore AT_IGNORE
v7: suppress TSan and remove superior check to avoid abort() in case of race
v8: proper suppressions (not inner function but itself)
Refs: ClickHouse#33957
Signed-off-by: Azat Khuzhin <[email protected]>