* breakpoint.c (breakpoint_init_inferior): Clean up the moribund
locations list.
(moribund_breakpoint_here_p): Record the moribund
location in the moribund_locations vector.
* breakpoint.h (moribund_breakpoint_here_p): Declare.
(displaced_step_fixup): Check if the breakpoint the thread was
trying to step over has been removed since having been placed in
the displaced stepping queue.
(adjust_pc_after_break): In non-stop mode, check for a moribund
breakpoint at the stop pc.
(handle_inferior_event): Don't retire moribund breakpoints on
TARGET_WAITKIND_IGNORE.
gdb/testsuite/
* gdb.mi/mi-nsmoribund.exp, gdb.mi/nsmoribund.c: New test.