configure.ac: convert --with-rpath from boolean to argument

[Gert Doering]

Hi,

On Mon, Jan 21, 2019 at 09:19:46AM +1100, Darren Tucker wrote:
> It might be possible to also roll the somewhat-similar AIX blibpath into
> this however the semantics are slightly different and I can't currently
> test it so that can be looked at later.

If you need something tested on recent AIX versions, just let me know.

gert
-- 
"If was one thing all people took for granted, was conviction that if you 
 feed honest figures into a computer, honest figures come out. Never doubted 
 it myself till I met a computer with a sense of humor."
                             Robert A. Heinlein, The Moon is a Harsh Mistress

Gert Doering - Munich, Germany                             gert at greenie.muc.de