Log Message:
libfilezilla: update to 0.12.1.

0.12.1 (2018-02-23)

+ Added fz::buffer::operator== and operator!=
- Fixed bug in fz::buffer::get(size_t)

0.12.0 (2018-02-16)

+ Added fz::datetime::operator bool
+ Added fz::datetime::get_rfc822 and fz::datetime::set_rfc822