Now calling WelsThreadJoin is enough to finish and clean up
the thread on all platforms.
This unifies the thread cleanup code between windows and unix.
Now all of the threading code should use the exact same codepaths
between windows and unix.
On arm, the exact same detection is done in WelsCPUFeatureDetect,
but in the x86 version of that function we use x86 cpuid for getting
the core count, and this is not available on all processors. For the
case when cpuid can't tell the core count, use the NDK function as
higher level API.
The thread lib itself doesn't build properly on android yet, but will
do so soon.
This allows making the WelsMultipleEventsWaitSingleBlocking
function work properly in unix, without polling. If a master
event is provided, the function first waits for a signal on
that event - once such a signal is received, it is assumed that
one of the individual events in the list have been signalled as
well. Then the function can proceed to check each of the semaphores
in the list using sem_trywait to find the first one of them that
has been signalled. Assuming that the master event is signalled
in pair with the other events, one of the sem_trywait calls
should succeed.
The same master event is also used in
WelsMultipleEventsWaitAllBlocking, to keep the semaphore values
in sync across calls to the both functions.
All users of the function passed the value corresponding to
"infinite", and the (currently unused) unix implementation of it
only supported infinite wait as well.
This avoids the risk of namespace collisions for named semaphores
(where the names are global for the whole machine), on platforms
where we strictly don't need to use the named semaphores.
This unifies the event creation interface, even if the event
name itself is unused on windows, allowing use the exact same
code to initialize events regardless of the actual platform.
Some ifdefs still remain in the event initialization code, since
some events are only used on windows.
Typedeffing WELS_EVENT as sem_t* makes the typedef behave similarly
to the windows version (typedeffed as HANDLE), unifying the code
that allocates and uses these event objects (getting rid of
most of the need for separate codepaths and ifdefs).
The two different variants of the threadlib basically are
win32 and unix - use _WIN32 to check for this consistently,
instead of occasionally using __GNUC__ to enable the unix
codepath. (__GNUC__ is also defined on mingw, which still is
a windows platform and should use the _WIN32 code.)
When adding the (dwMilliseconds % 1000) * 1000000 part
to ts.tv_nsec, the ts.tv_nsec field can grow larger than one
whole second. Therefore first add all of dwMilliseconds to
the tv_nsec field and add all whole seconds to the tv_sec
field instead - this way we make sure that the tv_nsec field
actually is less than a second.
Also use the __APPLE__ predefined define instead of MACOS for enabling
these code paths.
This also avoids having to link to the CoreServices framework in
order to get the Gestalt function.
This gets rid of the code that parses /proc/cpuinfo, and avoids
forking within the library.
The previous code also failed build on modern glibc versions
due to ignoring the return value of the system, read and write
system calls.
