clang -O2 -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations limits/_POSIX_SIGQUEUE_MAX.c -o limits/_POSIX_SIGQUEUE_MAX -D_POSIX_C_SOURCE=202405L -lm -lintl limits/_POSIX_SIGQUEUE_MAX.c:3:2: error: "_POSIX_SIGQUEUE_MAX is not defined" #error "_POSIX_SIGQUEUE_MAX is not defined" ^ 1 error generated.