Conditional breakpoints with unmet conditions would cause next and step
to skip the line.
This breakpoint changes the Kind field of proc.Breakpoint from a single
value to a bit field, each breakpoint object can represent
simultaneously a user breakpoint and one internal breakpoint (of which
we have several different kinds).
The breakpoint condition for internal breakpoints is stored in the new
internalCond field of proc.Breakpoint so that it will not conflict with
user specified conditions.
The breakpoint setting code is changed to allow overlapping one
internal breakpoint on a user breakpoint, or a user breakpoint on an
existing internal breakpoint. All other combinations are rejected. The
breakpoint clearing code is changed to clear the UserBreakpoint bit and
only remove the phisical breakpoint if no other bits are set in the
Kind field. ClearInternalBreakpoints does the same thing but clearing
all bits that aren't the UserBreakpoint bit.
Fixes#844
RequestManualStop will run concurrently with trapWait, since one writes
dbp.halt and the other reads it dbp.halt should be protected by a
mutex.
Updates #830
While implementing the gdbserial backend everything was changed to call
Detach to "close" a process so that gdbserial could do its clean up in
a single place. However the native implementation of Detach does not
actually kill processes we launched.
Fixes#821
