Add C11 Thread support (easy)

[kallisti5]

Mesa was asking about us getting C11 threads. From what I can tell we don't offer this today.

C11 Threads    POSIX Threads
thrd_create()  pthread_create()
thrd_current() pthread_self()
thrd_detach()  pthread_detach()
thrd_equal()   pthread_equal()
thrd_exit()    pthread_exit()
thrd_join()    pthread_join()

Today we offer BeOS native things like thread_id find_thread(const char *name); , and POSIX threads like pthread_t pthread_self(void);

[tqh]

I guess there are some types as well?

[kallisti5]

probably :-)

​http://open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3631.pdf

Getting the C11 Standard
C11 and C++11 are available from the ANSI store.  For C11, use this link:
http://webstore.ansi.org/RecordDetail.aspx?sku=INCITS%2fISO%2fIEC+9899‐2012.  For C++11, use this
link: http://webstore.ansi.org/RecordDetail.aspx?sku=INCITS%2fISO%2fIEC+14882‐2012 .  Each costs
$30 USD for PDF. The whole process takes only a few minutes.

hm.

[tqh]

Lets not buy it, we kind of do like challenges :)

[kallisti5]

lol. we definitely should reverse engineer something that only costs $30

[kallisti5]

oof. $60 each.

​https://webstore.ansi.org/Standards/INCITS/INCITSISOIEC98992012 ​https://webstore.ansi.org/Standards/INCITS/INCITSISOIEC148822012

Reverse engineering looking better and better :-D

[kallisti5]

​https://en.cppreference.com/w/c/thread there. free :-D

[pulkomandy]

Apparently this does not require anything specific in GCC, so we should be able to copy an implementation from a C library as we usually do (glibc 2.28 or later, or *BSD or musl).

musl has some thrd_* things: ​https://git.musl-libc.org/cgit/musl/tree/src/thread/thrd_create.c , it seems to call into musl internals directly FreeBSD docs: ​https://www.freebsd.org/cgi/man.cgi?query=thrd_create&apropos=0&sektion=0&arch=default&format=html says they implement it as "a thin wrapper over pthreds" so that may be easy to reuse

[pulkomandy]

It looks like we just need this one file from FreeBSD: ​https://xref.landonf.org/source/xref/freebsd-current/lib/libstdthreads/thrd.c

[korli]

Applied in hrev56041.