message: elle.log: beware of Windows paths
diff: #include <fstream>
  #include <mutex>
  -#include <boost/algorithm/string/erase.hpp>
  -#include <boost/algorithm/string/predicate.hpp>
  -#include <boost/algorithm/string/trim.hpp>
  +#include <boost/algorithm/string.hpp>
  #include <boost/tokenizer.hpp>
  #include <elle/Exception.hh>
  @@ -242,7 +240,9 @@ namespace elle
  make_logger(std::string const& targets)
  {
  auto const ts
  - = elle::print(targets,
  + // On Windows we might get a path that uses `\` as a
  + // separator. Escape it for elle::print.
  + = elle::print(boost::replace_all_copy(targets, "\\", "\\\\"),
  {
  {"pid", elle::system::getpid()},
  });
  