RFC: Do not call write_pc for "signal SIGINT"

[Michael Snyder]

Daniel Jacobowitz wrote:
> On Thu, Aug 28, 2008 at 11:09:56AM -0700, Michael Snyder wrote:
>> Hmmm, kind of opaque.  Your new code seems like the right
>> thing to do, but I don't understand the code that you're replacing.
>>
>> Isn't -1 supposed to mean the same as stop_pc?
> 
> Except that we call gdbarch_write_pc to replace the PC in this case,
> and that has side effects - take a look at a Linux example.
> 
>> And isn't signal 0 equivalent to no signal?
> 
> Yes, that's right.
> 
>>> This isn't the only place where Linux's internal errno codes can leak
>>> back into user programs because of how we fiddle orig_eax.  I'll file
>>> another bug report about that.
>> Now you've really lost me.  What have errno codes
>> got to do with this?
> 
> Sorry, take a look at the PR (gdb/2241) for more information.  When
> you hit C-c during select, and then type "signal SIGINT", the program
> gets errno 514 instead of EINTR.
> 
> Yes, I know, I need a testcase...

More than a testcase.  This isn't very well explained.
You didn't reference the PR in your original post, and
I'm still not sure how we're getting from SIGINT to
signal 0...