[boost] [1.60][spirit] Unmerged changes prevent compilation

Subject: [boost] [1.60][spirit] Unmerged changes prevent compilation
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2015-11-09 12:05:28

Hi,

The latest 1.60 beta RC fails to build Boost.Log because some changes in 
Boost.Spirit has not been merged to master. At least these patches need 
to be merged to master:

1. Fix the duplicate definition of strip_single_element_vector 
specialization:

https://github.com/boostorg/spirit/commit/4d8899fdfe26237d6d983a7ac5528d00f1416ec7

2. Fix an attempt to construct an instance of none_t:

https://github.com/boostorg/spirit/commit/534cf39f15ced047359ee8b6dfe434635fdcc500

3. Although it's not strictly a build breaker, this change fixes a bunch 
of warnings about signed/unsigned mismatch:

https://github.com/boostorg/spirit/pull/140

After applying those patches to the RC Boost.Log builds successfully.

These commits and the PR has been in develop for quite some time, could 
someone merge them to master, please?