WipeFreeSpace 2.6 released!

WipeFreeSpace 2.6 has just been released.
Important portability updates: WipeFreeSpace now compiles also on FreeBSD and macOS (as provided by Travis CI): https://app.travis-ci.com/github/bogdro/wipefreespace.
Fixed a potential compilation error.
Enabled GCC advanced code analysis.
Progress bar fixed.
Other small updates.
As usual, check the ChangeLog file for more information.