[Commits] [wesnoth/wesnoth] 57940f: Fix build with VS2015 and VS2017

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/wesnoth/wesnoth
  Commit: 57940f740585f4bdae3595bcc98082cebd1dc6cd
      https://github.com/wesnoth/wesnoth/commit/57940f740585f4bdae3595bcc98082cebd1dc6cd
  Author: Jyrki Vesterinen <sandgtx at gmail.com>
  Date:   2017-05-23 (Tue, 23 May 2017)

  Changed paths:
    M src/config.hpp

  Log Message:
  -----------
  Fix build with VS2015 and VS2017

The problem was that overloads of config_construct_unpacker::visit() only
accepted certain parameters as rvalue references. Because they weren't
function templates (they were functions of a class template), type
deduction didn't occur and their parameters were rvalue references instead
of universal references.

See: https://isocpp.org/blog/2012/11/universal-references-in-c11-scott-meyers