Remove noop functions in favor of conditional compilation

src/cli/self_update.rs

@@ -469,6 +469,7 @@ pub(crate) async fn install(
         do_write_env_files()?;
 
         if !opts.no_modify_path {
+            #[cfg(windows)]
             do_add_to_programs()?;
             do_add_to_path()?;
         }
@@ -1022,6 +1023,7 @@ pub(crate) fn uninstall(no_prompt: bool) -> Result<utils::ExitCode> {
 
     // Remove CARGO_HOME/bin from PATH
     do_remove_from_path()?;
+    #[cfg(windows)]
     do_remove_from_programs()?;
 
     // Delete everything in CARGO_HOME *except* the rustup bin

src/cli/self_update/unix.rs

@@ -123,14 +123,6 @@ pub(crate) fn do_write_env_files() -> Result<()> {
     Ok(())
 }
 
-pub(crate) fn do_add_to_programs() -> Result<()> {
-    Ok(())
-}
-
-pub(crate) fn do_remove_from_programs() -> Result<()> {
-    Ok(())
-}
-
 /// Tell the upgrader to replace the rustup bins, then delete
 /// itself.
 pub(crate) fn run_update(setup_path: &Path) -> Result<utils::ExitCode> {