Fix clippy and track in CI

`flake check` will run clippy.

nix-bindings-util/src/context.rs

@@ -1,6 +1,5 @@
 use anyhow::{bail, Result};
 use nix_bindings_bindgen_raw as raw;
-use std::os::raw::c_char;
 use std::ptr::null_mut;
 use std::ptr::NonNull;
 
@@ -11,6 +10,12 @@ pub struct Context {
     inner: NonNull<raw::c_context>,
 }
 
+impl Default for Context {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl Context {
     pub fn new() -> Self {
         let ctx = unsafe { raw::c_context_create() };
@@ -48,11 +53,7 @@ impl Context {
 
     pub fn clear(&mut self) {
         unsafe {
-            raw::set_err_msg(
-                self.inner.as_ptr(),
-                raw::err_NIX_OK,
-                b"\0".as_ptr() as *const c_char,
-            );
+            raw::set_err_msg(self.inner.as_ptr(), raw::err_NIX_OK, c"".as_ptr());
         }
     }
 
@@ -143,8 +144,8 @@ mod tests {
         unsafe {
             raw::set_err_msg(
                 ctx_ptr,
-                raw::err_NIX_ERR_UNKNOWN.try_into().unwrap(),
-                b"dummy error message\0".as_ptr() as *const std::os::raw::c_char,
+                raw::err_NIX_ERR_UNKNOWN,
+                c"dummy error message".as_ptr(),
             );
         }
     }

nix-bindings-util/src/nix_version.rs

@@ -65,7 +65,7 @@ pub fn parse_version(version_str: &str) -> (u32, u32, i32) {
     let parts = version_str.split('.').collect::<Vec<&str>>();
     let major = parts[0].parse::<u32>().unwrap();
     let minor = parts[1].parse::<u32>().unwrap();
-    let patch = if parts.get(2).map_or(false, |s| s.contains("pre")) {
+    let patch = if parts.get(2).is_some_and(|s| s.contains("pre")) {
         -1i32
     } else {
         parts