On Sat, Mar 19, 2016 at 12:38 PM, Vladimir Prus <vladimir.prus@gmail.com> wrote:

Release candidates for 1.61.0 beta 1 are now available:

    http://boost.cowic.de/rc/boost_1_61_0_b1_rc1.zip
    http://boost.cowic.de/rc/boost_1_61_0_b1_rc1.tar.bz2
    http://boost.cowic.de/rc/boost_1_61_0_b1_rc1.tar.gz
    http://boost.cowic.de/rc/boost_1_61_0_b1_rc1.7z

As always, the release managers would appreciate it if you download
the candidate of your choice and give building it a try. Please report
both success and failure, and anything else that is noteworthy.

Packaging: The .gz file expanded to "boost_master_3a94cde635254f92fa87e0e11ef52d08684b8225", instead of "boost_1_61_0_b1"

I successfully built the libraries with Apple's clang compiler. "Apple LLVM version 7.0.2 (clang-700.1.81)" 
with C++03, C++11, C++14, and c++1z

I was not successful building the libraries with clang ToT.
Boost.Python, in particular, had compile errors.
I don't know if this is a problem in Boost.Python, or in libc++.  (probably libc++)
I will continue to investigate. 
In any case, I don't think that this should hold up the beta release.

-- Marshall