It is supposed to print a help message without the usage
line. Although it is deprecated and has been removed as of FUSE 3.0,
filesystems in the wild still use it.
The goal is to fully support FUSE API version 3.0 while maintaining
API/ABI compatibility with code written for 2.6 (or even older).
* <fuse.h> now emits a compiler warning if it's included without
defining FUSE_USE_VERSION. It had been silently defaulted to the
latest supported version prior to this change. This is permissive
compared to the original FUSE, as it emits an error instead.
* <fuse.h> now emits a warning if FUSE_USE_VERSION is higher than what
can be provided.
* Added a macro FUSE_MAKE_VERSION(maj, min). It was missing from
librefuse <fuse.h>.
No actual API updates have been made (yet).
pho