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

[Paul Eggert]

Thanks for looking into this. Sorry about my confusion between 
strverscmp and filevercmp. As this bug report appears to be about 
filevercmp, glibc is not involved; it's only Gnulib and the utilities 
using Gnulib's filevercmp module.

As I now understand it, Gnulib filevercmp is intended to be consistent 
with Debian's version comparison (this is documented in filevercmp.c), 
so GNU Bug#35939 is therefore based on a misunderstanding, as Gnulib 
filevercmp is implementing the Debian spec correctly for this test case.

Perhaps the coreutils manual could be improved to make this all clearer, 
and perhaps it should refer to the Debian manual if it doesn't already.