TLS for Android (and iOS)

[Dan Olson]

Any TLS progress out there in LDC-land?

To pass thread/fiber unittests on iOS, I put in temporary workaround
using pthread_get/setspecific directly for the two threadlocals
(Thread.sm_this and Fiber.sm_this).  Now I can pass 74 of 85
druntime/phobos unittests on iOS.

If nobody is working on the emulated TLS for LDC, I will give it a try.
Nothing to lose.
-- 
Dan