Do not enable LLD if we don't build host code for targets that opt into it

Author: Kobzol

src/bootstrap/src/core/config/config.rs

@@ -1016,6 +1016,15 @@ impl Config {
                 continue;
             }
 
+            // The rust.lld option is global, and not target specific, so if we enable it, it will
+            // be applied to all targets being built.
+            // So we only apply an override if we're building a compiler/host code for the given
+            // override target.
+            // Note: we could also make the LLD config per-target, but that would complicate things
+            if !hosts.contains(&TargetSelection::from_user(&target)) {
+                continue;
+            }
+
             let default_linux_linker_override = match linker_override {
                 DefaultLinuxLinkerOverride::Off => continue,
                 DefaultLinuxLinkerOverride::SelfContainedLldCc => {