This introduces a catchpoint class that is used as the base class for
all catchpoints. init_catchpoint is rewritten to be a constructor
instead.
This changes the hierarchy a little -- some catchpoints now inherit
from base_breakpoint whereas previously they did not. This isn't a
problem, as long as re_set is redefined in catchpoint.
At this point, all implementations of breakpoints use the vtable. So,
we can now remove most function pointers from breakpoint_ops and
switch to using methods directly in the callers. Only the two "static
virtual" methods remain in breakpoint_ops.
This changes breakpoint_ops::print_one to return bool, and updates all
the implementations and the caller. The caller is changed so that a
NULL check is no longer needed -- something that will be impossible
with a real method.
The "catch load" code is reasonably self-contained, and so this patch
moves it out of breakpoint.c and into a new file, break-catch-load.c.
One function from breakpoint.c, print_solib_event, now has to be
exposed, but this seems pretty reasonable.
