rust-lld: fallback to the default linker if there's no path to the linker

Author: lqd

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -3116,12 +3116,22 @@ fn add_lld_args(
 
     let self_contained_linker = self_contained_cli || self_contained_target;
     if self_contained_linker && !sess.opts.cg.link_self_contained.is_linker_disabled() {
+        let mut linker_path_exists = false;
         for path in sess.get_tools_search_paths(false) {
-            cmd.arg({
-                let mut arg = OsString::from("-B");
-                arg.push(path.join("gcc-ld"));
-                arg
-            });
+            let linker_path = path.join("gcc-ld");
+            if linker_path.exists() {
+                linker_path_exists = true;
+                cmd.arg({
+                    let mut arg = OsString::from("-B");
+                    arg.push(linker_path);
+                    arg
+                });
+            }
+        }
+        if !linker_path_exists {
+            // As an additional sanity check, we do nothing if the sysroot doesn't contain the
+            // linker path at all.
+            return;
         }
     }