[Boost-build] <architecture> not exported/usable?

Subject: [Boost-build] <architecture> not exported/usable?
From: Bruce Stephens (bruce.r.stephens_at_[hidden])
Date: 2012-03-30 08:44:51

I've been trying to build on HP-UX (PA-RISC) with the acc toolset and
that worked except that
the shared library extension was wrong: .so rather than .sl.

That was straightforward to fix. I just changed types/lib.jam,
appending sl to SHARED_LIB
and adding a new variant

type.set-generated-target-suffix SHARED_LIB : <toolset>acc : sl ;

Easy (after some failed experiments, anyway).

A colleague noted that this isn't appropriate for Itanium, where the
extension is the more usual
.so. So I thought just using <architecture> would work:

type.set-generated-target-suffix SHARED_LIB : <toolset>acc
<architecture>parisc : sl ;

But that doesn't work (the libraries end up with .so extensions).
Should it? Works if I use

    ./b2 architecture=parisc

so that seems an acceptable workaround, but I can't help feeling that
bjam knows what
architecture it's building from, and as far as I can see that ought
already to be usable
from <architecture> and ought to have the value parisc for this
architecture, so what's wrong?