CFLAGS_WARN = -Weverything -Wfatal-errors -Wno-poison-system-directories CXX_STD_FLAGS = -std=c++98 CXX_STD_FLAGS = -std=c++11 CXX_STD_FLAGS = -std=c++14 CXX_STD_FLAGS = -std=c++17 CXX_STD_FLAGS = -std=c++20 CXX_STD_FLAGS = -std=c++23 CXX_STD_FLAGS = -std=c++11