[fuzzylite] force C++14 standard

doesn't build under C++17 due to using removed symbols

AI/CMakeLists.txt

@@ -35,6 +35,7 @@ if(NOT fuzzylite_FOUND)
 		add_compile_options(-Wno-error=deprecated-declarations)
 	endif()
 	add_subdirectory(FuzzyLite/fuzzylite EXCLUDE_FROM_ALL)
+	set_property(TARGET fl-static PROPERTY CXX_STANDARD 14) # doesn't compile under 17 due to using removed symbol(s)
 	add_library(fuzzylite::fuzzylite ALIAS fl-static)
 	target_include_directories(fl-static PUBLIC ${CMAKE_HOME_DIRECTORY}/AI/FuzzyLite/fuzzylite)
 endif()