[boost] Use of third-party libraries

Subject: [boost] Use of third-party libraries
From: Michael Shepanski (mps_at_[hidden])
Date: 2014-07-23 07:14:32

On one hand, there's this:

     "A Boost library *should not* use libraries other than Boost or the 
C++ Standard Library."
     (http://www.boost.org/development/reuse.html)

On the other hand, sometimes it just seems like common sense. E.g. 
Boost.Math uses NTL, MPFR, and others.

Now I'm trying to get quince and its backend libraries 
(quince_postgresql, quince_sqlite) into shape for blincubator. The job 
of the backends is to liaise between quince and other people's 
libraries: libpq and sqlite3. There is no getting around that. So I was 
hoping that the prohibition would be waived in this case, as it was in 
the case of Boost.Math.

The trouble I have is that quince_postgresql and quince_sqlite are *not* 
header-only, and their code that calls libpq and sqlite3 is in .cpp 
files. And yet I don't want them to break the boost build for people who 
don't need this stuff, and haven't installed either or both of those 
third-party libraries.

Any suggestions? Any precedents?

Thanks,
--- Michael