Index: cmake/caches/Fuchsia-stage2.cmake
===================================================================
--- cmake/caches/Fuchsia-stage2.cmake
+++ cmake/caches/Fuchsia-stage2.cmake
@@ -17,6 +17,8 @@
   set(LLVM_ENABLE_LLD ON CACHE BOOL "")
   set(CLANG_DEFAULT_LINKER lld CACHE STRING "")
 endif()
+set(CLANG_DEFAULT_CXX_STDLIB libc++ CACHE STRING "")
+set(CLANG_DEFAULT_RTLIB compiler-rt CACHE STRING "")
 
 # This is a "Does your linker support it?" option that only applies
 # to x86-64 ELF targets.  All Fuchsia target linkers do support it.
@@ -39,13 +41,24 @@
   set(BUILTINS_${target}-fuchsia_CMAKE_SYSTEM_NAME Fuchsia CACHE STRING "")
 endforeach()
 
+set(LIBUNWIND_ENABLE_SHARED OFF CACHE BOOL "")
+set(LIBUNWIND_USE_COMPILER_RT ON CACHE BOOL "")
+set(LIBUNWIND_INSTALL_LIBRARY OFF CACHE BOOL "")
+set(LIBCXXABI_USE_COMPILER_RT ON CACHE BOOL "")
+set(LIBCXXABI_ENABLE_SHARED OFF CACHE BOOL "")
+set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
+set(LIBCXXABI_ENABLE_STATIC_UNWINDER ON CACHE BOOL "")
+set(LIBCXXABI_INSTALL_LIBRARY OFF CACHE BOOL "")
+set(LIBCXX_USE_COMPILER_RT ON CACHE BOOL "")
+set(LIBCXX_ENABLE_SHARED OFF CACHE BOOL "")
+set(LIBCXX_ENABLE_STATIC_ABI_LIBRARY ON CACHE BOOL "")
+
 set(LLVM_RUNTIME_TARGETS "default;x86_64-fuchsia;aarch64-fuchsia;x86_64-fuchsia-asan:x86_64-fuchsia;aarch64-fuchsia-asan:aarch64-fuchsia" CACHE STRING "")
 foreach(target x86_64;aarch64)
   set(RUNTIMES_${target}-fuchsia_CMAKE_BUILD_WITH_INSTALL_RPATH ON CACHE BOOL "")
   set(RUNTIMES_${target}-fuchsia_CMAKE_SYSROOT ${FUCHSIA_${target}_SYSROOT} CACHE PATH "")
   set(RUNTIMES_${target}-fuchsia_CMAKE_SYSTEM_NAME Fuchsia CACHE STRING "")
   set(RUNTIMES_${target}-fuchsia_UNIX 1 CACHE BOOL "")
-  set(RUNTIMES_${target}-fuchsia_LLVM_ENABLE_LIBCXX ON CACHE BOOL "")
   set(RUNTIMES_${target}-fuchsia_LIBUNWIND_USE_COMPILER_RT ON CACHE BOOL "")
   set(RUNTIMES_${target}-fuchsia_LIBUNWIND_ENABLE_STATIC OFF CACHE BOOL "")
   set(RUNTIMES_${target}-fuchsia_LIBCXXABI_USE_COMPILER_RT ON CACHE BOOL "")