On macOS, make strip="symbols" not pass any options to strip

This makes the output with `strip="symbols"` match the result of just
calling `strip` on the output binary, minimizing the size of the binary.

Author: joshtriplett

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -977,14 +977,20 @@ fn link_natively<'a, B: ArchiveBuilder<'a>>(
     }
 
     if sess.target.is_like_osx {
-        if let Some(option) = osx_strip_opt(sess.opts.debugging_opts.strip) {
-            strip_symbols_in_osx(sess, &out_filename, option);
+        match sess.opts.debugging_opts.strip {
+            Strip::Debuginfo => strip_symbols_in_osx(sess, &out_filename, Some("-S")),
+            Strip::Symbols => strip_symbols_in_osx(sess, &out_filename, None),
+            Strip::None => {}
         }
     }
 }
 
-fn strip_symbols_in_osx<'a>(sess: &'a Session, out_filename: &Path, option: &str) {
-    let prog = Command::new("strip").arg(option).arg(out_filename).output();
+fn strip_symbols_in_osx<'a>(sess: &'a Session, out_filename: &Path, option: Option<&str>) {
+    let mut cmd = Command::new("strip");
+    if let Some(option) = option {
+        cmd.arg(option);
+    }
+    let prog = cmd.arg(out_filename).output();
     match prog {
         Ok(prog) => {
             if !prog.status.success() {
@@ -1002,14 +1008,6 @@ fn strip_symbols_in_osx<'a>(sess: &'a Session, out_filename: &Path, option: &str
     }
 }
 
-fn osx_strip_opt<'a>(strip: Strip) -> Option<&'a str> {
-    match strip {
-        Strip::Debuginfo => Some("-S"),
-        Strip::Symbols => Some("-x"),
-        Strip::None => None,
-    }
-}
-
 fn escape_string(s: &[u8]) -> String {
     str::from_utf8(s).map(|s| s.to_owned()).unwrap_or_else(|_| {
         let mut x = "Non-UTF-8 output: ".to_string();