[RFA] Debug hooks

[Neil Booth]

Bernd Schmidt wrote:-

> I'd prefer to put a null pointer into the function table and check for
> it.

That's the way I originally preferred with the target stuff.  Mark
vetoed it on the grounds he didn't want us to have to remember what
could be NULL.  In view of what rth said about a do-nothing struct
I'll make dummy functions for everything since something will tend to
want them anyway.  OK?

> Presumably there are no ordering constraints between dwarf2out_frame_init
> and the non-dwarf2 init functions?

Good question.  I'm not sure - I'll have a look.  Unforunately I'm not
a debug expert so it might be hard for me to tell :-(

> This seems unrelated?  I'm not enough of a texinfo expert to know what it
> does.

Yes, just fixing markup from my previous target patch.

Neil.