POWER PC-relative addressing and new text relocations

[Florian Weimer]

At Cauldron, the question came up whether the dynamic loader needs to
be taught about the new relocations for PC-relative addressing.

I think they would only matter if we supported PC-relative addressing
*and* text relocations.  Is that really necessary?

These text relocations would not work reliably anyway because the
maximum displacement is not large enough.  For example, with the
current process layout, it's impossible to reach shared objects from
the main program and vice versa.  And some systems might want to add
additional randomization, so that shared objects are not mapped closed
together anymore.