--- llvm-project/libcxx/CMakeLists.txt
+++ llvm-project/libcxx/CMakeLists.txt
@@ -242,7 +242,7 @@ option(LIBCXX_ENABLE_NEW_DELETE_DEFINITIONS
   "Build libc++ with definitions for operator new/delete. These are normally
    defined in libc++abi, but this option can be used to define them in libc++
    instead. If you define them in libc++, make sure they are NOT defined in
-   libc++abi. Doing otherwise is an ODR violation." OFF)
+   libc++abi. Doing otherwise is an ODR violation." ON)
 # Build libc++abi with libunwind. We need this option to determine whether to
 # link with libunwind or libgcc_s while running the test cases.
 option(LIBCXXABI_USE_LLVM_UNWINDER "Build and use the LLVM unwinder." OFF)