mingw lacks the counterpart to PTHREAD_MUTEX_INITIALIZER, so the
best we can do is portably expose once-only runtime initialization.
* src/util/threads.h (virOnceControlPtr): New opaque type.
(virOnceFunc): New callback type.
(virOnce): New prototype.
* src/util/threads-pthread.h (virOnceControl): Declare.
(VIR_ONCE_CONTROL_INITIALIZER): Define.
* src/util/threads-win32.h (virOnceControl)
(VIR_ONCE_CONTROL_INITIALIZER): Likewise.
* src/util/threads-pthread.c (virOnce): Implement in pthreads.
* src/util/threads-win32.c (virOnce): Implement in WIN32.
* src/libvirt_private.syms: Export it.
The util/threads.c/h code already has APIs for mutexes,
condition variables and thread locals. This commit adds
in code for actually creating threads.
* src/libvirt_private.syms: Export new symbols
* src/util/threads.h: Define APIs virThreadCreate, virThreadSelf,
virThreadIsSelf and virThreadJoin
* src/util/threads-win32.c, src/util/threads-win32.h: Win32
impl of threads
* src/util/threads-pthread.c, src/util/threads-pthread.h: POSIX
impl of threads