#93 vfs::zip unable to open files in directories containing upper case

[RP.]

How to invoke bug:
1. Mount archive containing directory with upper case in name using vfs::zip::Mount.
2. cd to directory with upper case.
3. open any file from this folder returns:

% open xxx.txt r
couldn't open "xxx.txt": no such file or directory

Note: glob works fine in every directory.