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

Index: lld/tools/lld/CMakeLists.txt
--- lld/tools/lld/CMakeLists.txt.orig
+++ lld/tools/lld/CMakeLists.txt
@@ -15,10 +15,15 @@ target_link_libraries(lld
   lldCOFF
   lldDriver
   lldELF
-  lldMachO2
   lldMinGW
   lldWasm
   )
+
+if (LLD_ENABLE_MACHO)
+  target_link_libraries(lld
+    lldMachO2
+    )
+endif()
 
 install(TARGETS lld
   RUNTIME DESTINATION bin)
