glib versions prior to 2.31.0 require an explicit g_thread_init() call
to enable multi-threading.
Failure to initialize threading causes glib to take single-threaded code
paths without synchronization. For example, the g_slice allocator will
crash due to race conditions.
Fix this for all QEMU tool programs (qemu-nbd, qemu-io, qemu-img) by
moving the g_thread_init() call from vl.c:main() into a new
osdep.c:thread_init() constructor function.
thread_init() has __attribute__((constructor)) and is automatically
invoked by the runtime during startup.
We can now drop the "simple" trace backend's g_thread_init() call since
thread_init() already called it.
Note that we must keep coroutine-gthread.c's g_thread_init() call which
is located in a constructor function. There is no guarantee for
constructor function ordering so thread_init() may only be called later.
Reported-by: Mario de Chenno <mario.dechenno@unina2.it>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
ae2990c259