[binutils-gdb] btrace: async

[sergiodj+buildbot@redhat.com]

*** TEST RESULTS FOR COMMIT a6b5be76f94664406def040d79ac8bc4d4aa8bd0 ***

Author: Markus Metzger <markus.t.metzger@intel.com>
Branch: master
Commit: a6b5be76f94664406def040d79ac8bc4d4aa8bd0

btrace: async

The record btrace target runs synchronous with GDB.  That is, GDB steps
resumed threads in record btrace's to_wait method.  Without GDB calling
to_wait, nothing happens 'on the target'.

Check for further expected events in to_wait before reporting the current
event and mark record btrace's async event handler in async mode.

gdb/
	* record-btrace.c (record_btrace_maybe_mark_async_event): New.
	(record_btrace_wait): Call record_btrace_maybe_mark_async_event.