Index: cmake/caches/Apple-stage2.cmake
===================================================================
--- cmake/caches/Apple-stage2.cmake
+++ cmake/caches/Apple-stage2.cmake
@@ -38,6 +38,7 @@
 set(LIBCXX_INSTALL_LIBRARY OFF CACHE BOOL "")
 set(LIBCXX_INSTALL_HEADERS ON CACHE BOOL "")
 set(LIBCXX_INCLUDE_TESTS OFF CACHE BOOL "")
+set(LIBCXX_USE_COMPILER_RT ON CACHE BOOL "")
 set(LLVM_LTO_VERSION_OFFSET 3000 CACHE STRING "")
 
 # Generating Xcode toolchains is useful for developers wanting to build and use