diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6948010..0031fa8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -37,6 +37,19 @@ if(DEFINED MSVC)
     add_definitions(-D_USE_MATH_DEFINES)
 endif()
 
+if((CMAKE_CXX_COMPILER_ID MATCHES "Clang") AND (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 17))
+    include(CheckCXXSymbolExists)
+    if(cxx_std_20 IN_LIST CMAKE_CXX_COMPILE_FEATURES)
+        set(header version)
+    else()
+        set(header ciso646)
+    endif()
+
+    check_cxx_symbol_exists(_LIBCPP_VERSION ${header} LIBCPP)
+    if(LIBCPP)
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fexperimental-library")
+    endif()
+endif()
 
 add_subdirectory(libtermbench)
 add_subdirectory(tb)