diff --git a/libcxxabi/CMakeLists.txt b/libcxxabi/CMakeLists.txt
--- a/libcxxabi/CMakeLists.txt
+++ b/libcxxabi/CMakeLists.txt
@@ -96,9 +96,17 @@
        "Whether the libc++abi tests should link with the shared libc++abi library"
        ${LIBCXXABI_ENABLE_SHARED})
 
+if(DEFINED LIBCXX_ENABLE_SHARED)
+  set(_default_LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXX ${LIBCXX_ENABLE_SHARED})
+else()
+  set(_default_LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXX ON)
+endif()
+
 option(LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXX
        "Whether the libc++abi tests should link with the shared libc++ library"
-       ${LIBCXX_ENABLE_SHARED})
+       ${_default_LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXX})
+
+unset(_default_LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXX)
 
 cmake_dependent_option(LIBCXXABI_INSTALL_STATIC_LIBRARY
   "Install the static libc++abi library." ON