[libcxxabi] HandleLLVMOptions in out of tree build

Differential revision: https://reviews.llvm.org/D33753

git-svn-id: https://llvm.org/svn/llvm-project/libcxxabi/trunk@304664 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/cmake/Modules/HandleOutOfTreeLLVM.cmake b/cmake/Modules/HandleOutOfTreeLLVM.cmake
index 1dcaf90..8e74208 100644
--- a/cmake/Modules/HandleOutOfTreeLLVM.cmake
+++ b/cmake/Modules/HandleOutOfTreeLLVM.cmake
@@ -93,6 +93,7 @@
   endif()
   if (LLVM_FOUND)
     include(AddLLVM OPTIONAL)
+    include(HandleLLVMOptions OPTIONAL)
   endif()
 
   # LLVM Options --------------------------------------------------------------