* user-config.jam is the suggested way for adding toolset for Boost.Build.
* always specify toolset when running b2, so we can build boost with
specified compiler instead of the default one guessed by boost building system.
Signed-off-by: Kefu Chai <kchai@redhat.com>
config.hpp does not exist if boost is not configured. so a boost source
directory unpacked from dist tarball does not have this file. the
bootstrap.sh instead, it is used to create the necessary config files
for jam.
Signed-off-by: Kefu Chai <kchai@redhat.com>
