Re: bcp namespace aliasing broken, impacts package providers, shared libraries unusable since 1.69

From: Peter Dimov (pdimov_at_[hidden])
Date: 2019-05-26 14:39:59

> But as a first step I think that we need to add a Travis test to tools/bcp 
> that exercises the scenario we want to fix.

I've looked into this and we have some issues we probably need to address 
even before getting to namespace aliasing.

1. Since tools/boost_install and libs/headers are now needed by Jamroot, it 
might be better if we install them by default when `build` is requested. 
(libs/config is also needed by Jamroot, but almost every other library needs 
it as a dependency, so this usually doesn't manifest as a problem in 
practice.)

2. When I add them by hand, bcp installs more than needed, because 
tools/boost_install/test references a number of libraries such as container, 
log, python, and so on; we don't need these for typical uses.

3. Installing these libraries exposed issues with them:

3a. Log doesn't work because it has jamfiles in libs/log/config, which is 
not copied (just `build` and `src` are.)
3b. Test doesn't work because it uses predef.check in its Jamfile, but 
Predef is not copied.

Apart from that, https://travis-ci.org/boostorg/bcp/builds/537447552