[m-rev.] for post-commit review: fix mantis bug 361

[Julien Fischer]

On Thu, 18 Sep 2014, Paul Bone wrote:

> Can we make debug imply decldebug and remove the explicit "decldebug" grade
> modifier?  To say it another way, if I want a debugging grade is it ever
> "bad" to add the declrative debugging features?

To the best of my knowledge the is still some extra overhead involved
with the full decldebug grade, which is why they are still separate.

> Similarly, I think that the par grade component on the low level C backend
> should always imply the stseg grade component.

The unfortunate overloading of the par component to mean different
things for the high- and low-level C backends is already confusing
enough.  I don't want to make it more confusing by have par imply stseg
in some cases as well.

>  And AFAIK it's rare that someone would want the stseg feature in a
>  non-parallel build.

The configure script currently enables stack segments by default for
every for every low-level C grade except {asm_fast,reg,none}.gc and
{asm_fast,reg,none}.gc.trseg, so it's hardly something that is
restricted to the par grade.  (I am in favour of enabling stack segments
by default for every low-level C grade.)

Cheers,
Julien.