Fix some issues as noted by @lilyball

Co-authored-by: Lily Ballard <lily@sb.org>

README.md

@@ -255,6 +255,18 @@ brew install ffsend
 ffsend --help
 ```
 
+#### macOS: Nix package
+_Note: The Nix package is currently not automatically updated, therefore it
+might be slightly outdated. Open an issue if you believe an important update
+is missing._
+
+```bash
+nix-channel --update
+nix-env --install ffsend
+
+ffsend --help
+```
+
 #### macOS: Prebuilt binaries
 Check out the [latest release][github-latest-release] assets for a macOS binary.
 If it isn't available yet, you may use an artifact from a

build.rs

@@ -1,6 +1,6 @@
 fn main() {
     // xclip and xsel paths are inserted at compile time on Linux
-    #[cfg(target_os = "linux")]
+    #[cfg(all(feature = "clipboard", target_os = "linux"))]
     {
         println!("cargo:rerun-if-env-changed=XCLIP_PATH");
         println!("cargo:rerun-if-env-changed=XSEL_PATH");

src/util.rs

@@ -352,7 +352,7 @@ impl ClipboardType {
         }
     }
 
-    /// Set clipboar contents through the selected clipboard type.
+    /// Set clipboard contents through the selected clipboard type.
     pub fn set(&self, content: String) -> Result<(), ClipboardError> {
         match self {
             #[cfg(not(target_os = "linux"))]