chore(tvix/store): add fuse feature

This brings in fuse (via the `fuser` crate), and adds pkg-config and
libfuse to the dev shell, so `cargo build` can link against it.

Change-Id: I0d11607490e27d946bdf92b0b9e45f9ab644ba74
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8664
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI

tvix/store/Cargo.toml

@@ -30,10 +30,18 @@ bytes = "1.4.0"
 smol_str = "0.2.0"
 serde_json = "1.0"
 
+[dependencies.fuser]
+optional = true
+version = "0.12.0"
+
 [dependencies.tonic-reflection]
 optional = true
 version = "0.5.0"
 
+[dependencies.libc]
+optional = true
+version = "0.2.144"
+
 [build-dependencies]
 prost-build = "0.11.2"
 tonic-build = "0.8.2"
@@ -44,5 +52,6 @@ tempfile = "3.3.0"
 tonic-mock = { git = "https://github.com/brainrake/tonic-mock", branch = "bump-dependencies" }
 
 [features]
-default = ["reflection"]
+default = ["fuse", "reflection"]
+fuse = ["dep:fuser", "dep:libc"]
 reflection = ["tonic-reflection"]