GDB 5.0 won't build on GNU/Linux/sparc

[Alexandre Oliva]

On May 20, 2000, Alexandre Oliva <aoliva@cygnus.com> wrote:

> On GNU/Linux/sparc, it builds correctly, but it still doesn't work
> :-( child_resume is called with step==1, and aborts because
> SOFTWARE_SINGLE_STEP_P is also 1.

This patch fixes this problem, and now it appears to work (not that I
have tested it extensively!)

The problem was that, when resume issued the software single step
command, it cleared `step'.  Later on, it would test whether step was
zero and think it had been asked to `continue'.  Ok to install?