bug#35939: version sort is incorrect with hyphen-minus

[Paul Eggert]

GNU sort uses the same algorithm as glibc strverscmp, and this algorithm has 
changed only once since strverscmp was added to glibc in 1997. The change was 
made in 2009, to fix this bug:

https://sourceware.org/bugzilla/show_bug.cgi?id=9913
Has the Debian version-comparison algorithm changed since 1997? If so, could you 
give details about the changes to the Debian algorithm? Perhaps glibc should be 
changed to stay consistent with Debian.