--- a/CMakeLists.txt
+++ a/CMakeLists.txt
@@ -115,3 +115,4 @@
+target_compile_features(caf_internal INTERFACE cxx_std_17)
# TODO: simply set CXX_STANDARD when switching to CMake ≥ 3.9.6
-if(NOT CMAKE_CROSSCOMPILING)
+if(0)
try_compile(caf_has_cxx_17