Do not check for --jobserver-fds on windows

Since the manual specifies that only `--jobsewrver-auth` will be used
and windows does not have the concept of fds anyway.

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

src/job_token/windows.rs

@@ -24,10 +24,7 @@ impl JobServerClient {
         let s = var
             .to_str()?
             .split_ascii_whitespace()
-            .filter_map(|arg| {
-                arg.strip_prefix("--jobserver-fds=")
-                    .or_else(|| arg.strip_prefix("--jobserver-auth="))
-            })
+            .filter_map(|arg| arg.strip_prefix("--jobserver-auth="))
             .find(|s| !s.is_empty())?;
 
         let name = CString::new(s).ok()?;