[RFC] Support temporary breakpoints in runto_main.

[Joel Brobecker]

> If I imagine I'm new to gdb and see the name runto_main I can well
> imagine not expecting the implementation of that command to leave the
> breakpoint behind.  Leaving the breakpoint behind is not something I
> would expect from that name.

FWIW, the AdaCore's gdb-testsuite framework defines a "runto" method,
and it does set a temporary breakpoint by default (with the option
of making it permanent). Same reasoning as yours went into the "design"
of this method's interface.

Not sure if it's worth spending time changing this, but I would
welcome the change...

-- 
Joel