gcontextspecificgroup: Wait until stop_func is done
Currently, the stop_func
is executed on an extra thread, and the
g_context_specific_group_remove
function returns before the stop_func
finishes. It may happen that the stop_func
is never executed if the
program terminates soon after calling it. Let's wait until the stop_func
is done.
Fixes: #3258 (closed)