Changes applied in commit 4fabde349f broke
VxWorks tests and examples, many of which crash with error:
```
pthreadLib: unable to create POSIX thread internal attributes.
```
This error appeared in multiple tests, but was tested on tst_QSignalSpy,
where it was 100% reproducible (I haven't check other tests for
reproducibility).
This above error is printed when VxWorks task starts and initializes its
pthread containers. Pthread starting procedure results in error
`S_objLib_OBJ_ID_ERROR`, on which documentation states that it means
"The <tid> parameter is an invalid task ID". This happens because
VxWorks pthread implementation clears its internal data, and only then
passes control to `taskExit` system procedure, which calls thread_local
destructors. Any calls to `pthread` routines which require current
thread internal data ends with error and termination.
While VxWorks uses clang internally, it implements `__cxa_thread_atexit`
and `__cxa_thread_atexit_impl`, which makes it pass `TEST_cxa_atexit` in
CMake, even thou their call order is different than on other platforms.
Enable QT_FEATURE_broken_threadlocal_dtors for VxWorks by failing
compilation of cxa_thread_atexit* tests, which fixes the crashes on
VxWorks.
Task-number: QTBUG-115777
Change-Id: I4109b66903333a94301afe7fe5634ac4365a70b4
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
a295f4f913