[$] Case-insensitive ext4

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Handling file names in a case-insensitive way for Linux filesystems has
been an ongoing
discussion topic for many years. It is a (dubious) feature of filesystems
for other operating systems (e.g. Android, Windows, macOS), but Linux has
limited support for it. Over the last year or more, Gabriel Krisman
Bertazi has been working on the problem for
ext4, but it is a messy one to solve. He recently posted his latest patch
set, which reflects some changes made at the behest of Linus Torvalds.