cmake HAS_CXX17 examples

erthink/libmdbx CMakeLists.txt :524 

list(FIND CMAKE_CXX_COMPILE_FEATURES cxx_std_17 HAS_CXX17)

erthink/libmdbx CMakeLists.txt :537 

elseif(NOT HAS_CXX17 LESS 0 AND NOT (CMAKE_COMPILER_IS_CLANG AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5))

erthink/libmdbx cmake/compiler.cmake :1103 

list(FIND CMAKE_CXX_COMPILE_FEATURES cxx_std_17 HAS_CXX17)