Don't build MachO2 support in lld.  This code reaches into libunwind
internals.

Index: tools/lld/tools/lld/lld.cpp
--- tools/lld/tools/lld/lld.cpp.orig
+++ tools/lld/tools/lld/lld.cpp
@@ -148,10 +148,12 @@ static int lldMain(int argc, const char **argv, llvm::
     return !elf::link(args, exitEarly, stdoutOS, stderrOS);
   case WinLink:
     return !coff::link(args, exitEarly, stdoutOS, stderrOS);
+#if 0
   case Darwin:
     return !macho::link(args, exitEarly, stdoutOS, stderrOS);
   case DarwinOld:
     return !mach_o::link(args, exitEarly, stdoutOS, stderrOS);
+#endif
   case Wasm:
     return !lld::wasm::link(args, exitEarly, stdoutOS, stderrOS);
   default:
