[committed] Ensure pc-relative calls can reach their target on

[Cary Coutant]

> I'm not aware of support within ELF for multiple unnamed sections.  I
> believe the HP linker can do all kinds of interesting things with unnamed
> subspaces.  They can have different sort keys, flags, etc.

Not multiple unnamed sections -- just multiple sections with the same
name. There's nothing in ELF that requires all sections to have unique
names.

<nostalgia>
All that extra stuff in SOM was mostly for MPE. I added sort keys
because I was tired of constantly fielding requests from the MPE team
to change the default layout order of the subspaces during the initial
bring-up. That let them control the layout by setting the sort key for
each subspace in crt0.o (that was essentially our "linker script" at
the time). On the HP-UX side, sort keys made it possible to put
"bracketing" sections (subspaces) -- both opening and closing -- in
crt0.o; no need for crtn.o/crtend.o.
</nostalgia>

-cary