diff --git a/nc_cxx.cmake b/nc_cxx.cmake
index 49a6e66..6693253 100644
--- a/nc_cxx.cmake
+++ b/nc_cxx.cmake
@@ -24,6 +24,10 @@ append_compile_flag ("-std=c++1z")
 append_compile_flag ("-fpermissive")
 append_compile_flag ("/std:c++latest")
 
+# try to use clangs libc++ under the assumption that gcc will fail this test
+# and clang will pass (if it is present). this is necessary because some
+# libstdc++ headers don't behave well under c++17/clang.
+append_compile_flag ("-stdlib=libc++")
 
 ###############################################################################
 # find the gcc or clang filesystem library and append to libs if needed