Support for "break *ADDRESS thread THREADNO"

[Stan Shebs]

Eli Zaretskii wrote:

>
>Or maybe a command option "break --thread=ID *ADDR".  (Or did we
>decide to not use such syntax?)
>
"--" is still valid expression syntax, though unlikely in
that context.

Looking at the keyboard, I don't see much that is not already
part of language or GDB syntax. How about '/', which has no
unary usage, and is already used for command modifiers?

Stan