cc -pthread -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations locale/LC_MESSAGES_MASK.c -o locale/LC_MESSAGES_MASK -D_POSIX_C_SOURCE=202405L -lm -lpthread -liconv locale/LC_MESSAGES_MASK.c:3:2: error: "LC_MESSAGES_MASK is not defined" #error "LC_MESSAGES_MASK is not defined" ^ 1 error generated.