crate works with macFUSE 4.0.5 but needs build.rs update

[mike-kfed]

I checked on my Apple M1 powered machine (where the old osxfuse 3.x does not run anymore). Here are the steps to reproduce:

• install macFUSE 4.0.5 from the osxfuse.github.io website binary package
• brew install pkg-config
• edit fuse-sys/build.rs and also use LIBFUSE_NAME = "fuse" for macOS like for any OS
• cargo run --example hello -- mountpoint works fine
• cargo test runs fine

I was thinking to make a pull request for this, but I am not sure how you want to handle this. One option to check for the macFUSE 4.x series is to test for existence of the file /Library/Filesystems/macfuse.fs/Contents/Resources/mount_macfuse as the program was renamed from osxfuse 3.x to macfuse 4.x = this makes sure the system has v4 installed. This file check can be added to build.rs to decide the LIBFUSE_NAME, but this means the LIBFUSE_NAME cannot be static anymore (at least I think it'll come from a function, unless there is some macro magic that I don't know of).

Other option is to make macfuse 4 support a cfg-feature flag? May make sense, as version 4 and above are no longer open source and this way users actively have to choose to compile against the non-OSS version? However osxfuse v3 is deprecated on homebrew, so easy v3 install will go away at some point (and already went away on M1) meaning the binary only v4 install is the future as of now.

for any of those two options, install instructions for macOS need updating accordingly. Not sure how this will integrate with CI testing though. I will happily provide a pull request for all this if you want, just let me know how you prefer to check for osxfuse v3 vs. v4 on macOS in the build.rs

[Minoru]

fuse-rs is in a bit of a languishing state, you might want to open a similar issue with https://github.com/cberner/fuser which is a fork of this project and is more actively developed.