openbsd-i686: use lld as linker by default

standard binutils on openbsd is too old to do proper job with i128
code.

Author: semarie

src/librustc_target/spec/i686_unknown_openbsd.rs

@@ -15,6 +15,7 @@ pub fn target() -> TargetResult {
     base.cpu = "pentium4".to_string();
     base.max_atomic_width = Some(64);
     base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m32".to_string());
+    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-fuse-ld=lld".to_string());
     base.stack_probes = true;
 
     Ok(Target {