* m4/gnulib-common.m4 (gl_COMMON_BODY): Emit definition of
_GL_ASYNC_SAFE into config.h.
* lib/nanosleep.c (sighandler): Mark as _GL_ASYNC_SAFE.
* lib/fatal-signal.h (at_fatal_signal): Add _GL_ASYNC_SAFE marker to
argument.
* lib/fatal-signal.c (action_t, uninstall_handlers,
fatal_signal_handler): Mark as _GL_ASYNC_SAFE.
* lib/clean-temp.c (cleanup_action): Mark as _GL_ASYNC_SAFE.
* lib/wait-process.c (cleanup_slaves, cleanup_slaves_action): Mark as
_GL_ASYNC_SAFE.
* lib/c-stack.h (c_stack_action): Add _GL_ASYNC_SAFE marker to argument.
* lib/c-stack.c: Add _GL_ASYNC_SAFE markers.