Boost 1.85 removed some deprecated code in filesystem module which is
still used in columnstore:
- The boost/filesystem/convenience.hpp was removed but columnstore does
not use any functionality from that file except indirect includes.
Therefore this include is removed or replaced with more general
boost/filesystem.hpp. The convenience.hpp header file was deprecated
in filesystem V3 introduced in Boost 1.46.0.
- `normalize` method was removed and users are suggested to replace it
with `lexically_normal` method, which was introduced in Boost 1.60.0.
Original `normalize` call is preserved for backward compatibility with
old Boost version, however`, `lexically_normal` method is preferably
used with Boost 1.60.0 and newer.
- The `copy_option` was removed in favor of `copy_options` (note the
trailing 's'), but enum values were renamed. Namely, `fail_if_exists`
is replaced with `none` and `overwrite_if_exists` is replaced with
`overwrite_existing`. The `copy_options` was introduced in Boost
1.74.0.
New form is used instead, but a backward compatibility layer for Boost
1.73.0 and older was introduced in boost_copy_options_compat.hpp file.
This solution seems to be less awkward than using multiple #if #else
#endif blocks in source code.
