thrd: Work around thrd_join bug on AIX 7.3.1

[Bruno Haible]

On AIX 7.3.1, I see these two test failures:

FAIL: test-thrd_create
======================

../../gltests/test-thrd_create.c:61: assertion 'ret == MAGIC' failed
FAIL test-thrd_create (exit status: 134)

FAIL: test-thrd_exit
====================

../../gltests/test-thrd_exit.c:65: assertion 'ret == MAGIC' failed
FAIL test-thrd_exit (exit status: 134)

The cause is:
  - In AIX 7.[12], the type thrd_start_t is broken, and accordingly it was
    impossible to implement thrd_join correctly, since the exit code types
    did not match.
  - In AIX 7.3.1 they fixed the thrd_start_t type. But the thrd_join is still
    broken, for no good reason.

This patch adds a workaround.


2023-08-18  Bruno Haible  <bruno@clisp.org>

        thrd: Work around thrd_join bug on AIX 7.3.1.
        * m4/threads_h.m4 (gl_THREADS_H): Test against AIX 7 thrd_join bug. Set
        BROKEN_THRD_JOIN.
        (gl_THREADS_H_DEFAULTS): Initialize BROKEN_THRD_JOIN.
        * m4/thrd.m4 (gl_FUNC_THRD_JOIN): Set REPLACE_THRD_* to 1 also if
        BROKEN_THRD_JOIN is 1. Define BROKEN_THRD_START_T_OR_JOIN instead of
        BROKEN_THRD_START_T.
        * modules/threads-h (Makefile.am): Substitute BROKEN_THRD_JOIN.
        * lib/threads.in.h (rpl_thrd_t, thrd_t): Define also if BROKEN_THRD_JOIN
        is 1.
        * lib/thrd.c: Test BROKEN_THRD_START_T_OR_JOIN instead of
        BROKEN_THRD_START_T.
        * doc/posix-functions/thrd_join.texi: Update.
        * doc/posix-functions/thrd_exit.texi: Likewise.

        thrd: Refactor.
        * m4/thrd.m4 (gl_FUNC_THRD_JOIN): Define BROKEN_THRD_JOIN_NULL, not
        BROKEN_THRD_JOIN. Rename gl_cv_func_thrd_join_works to
        gl_cv_func_thrd_join_null_works.
        * lib/thrd.c: Test BROKEN_THRD_JOIN_NULL instead of BROKEN_THRD_JOIN.

0001-thrd-Refactor.patch
Description: Text Data

0002-thrd-Work-around-thrd_join-bug-on-AIX-7.3.1.patch
Description: Text Data