clone: implement clone3 syscall decoding

clone: implement clone3 syscall decoding

* configure.ac (AC_CHECK_HEADERS): Check for linux/sched.h presence.
(AC_CHECK_TYPES): Check for struct clone_args in <linux/sched.h>.
* clone.c: Include "print_fields.h".
(struct strace_clone_args): New type.
(print_nonzero_bytes): New function.
(SYS_FUNC(clone3)): New decoder.
* linux/syscallent-common.h ([BASE_NR + 435]): Wire up clone3.
* NEWS: Mention this change.
* tests/clone3.c: New file.
* tests/clone3-Xabbrev.c: Likewise.
* tests/clone3-Xraw.c: Likewise.
* tests/clone3-Xverbose.c: Likewise.
* tests/clone3-success.c: Likewise.
* tests/clone3-success-Xabbrev.c: Likewise.
* tests/clone3-success-Xraw.c: Likewise.
* tests/clone3-success-Xverbose.c: Likewise.
* tests/clone3-success.test: New test.
* tests/Makefile.am (check_PROGRAMS): Add clone3-success,
clone3-success-Xabbrev, clone3-success-Xraw, and
clone3-success-Xverbose.
(DECODER_TESTS): Add clone3-success.test.
* tests/gen_tests.in (clone3, clone3-Xabbrev, clone3-Xraw,
clone3-Xverbose, clone3-success-Xabbrev, clone3-success-Xraw,
clone3-success-Xverbose): New entries.
* tests/pure_executables.list: Add clone3, clone3-Xabbrev, clone3-Xraw,
and clone3-Xverbose.
* tests/.gitignore: Add clone3, clone3-Xabbrev, clone3-Xraw,
clone3-Xverbose, clone3-success, clone3-success-Xabbrev,
clone3-success-Xraw, and clone3-success-Xverbose.

Co-Authored-by: Dmitry V. Levin <ldv@altlinux.org>