loader: Mark the stack as executable if possible.

[Mike McCormack]

Alexandre Julliard wrote:

> My impression from reading MSDN is that Windows pops up a message box
> too, but I don't have a way of confirming this. And I'm not convinced
> that "make everything work and ignore security" is the right default,
> we all know how well this worked for Windows.

Sure, don't ignore security, but there's not point in asking users 
questions they don't know how to answer.

90% of the time the right answer is going to be "let the program 
continue", so if users keep seeing this dialog box like this:

   /-----------------------------------------\
   |   foo.exe did something questionable    |
   |   that you probably won't understand.   |
   |             Is that OK?                 |
   |            [Yes]    [No]                |
   \-----------------------------------------/

they'll be trained to say "yes".  A programmer might know the correct 
answer, but that doesn't help users.

If you can't determine the right answer automagically, I don't see the 
point in bugging the user for it, as they're not going to know any better.

Mike