cc -pthread -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations unistd/O_CLOFORK.c -o unistd/O_CLOFORK -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lcrypt -latomic unistd/O_CLOFORK.c:2:17: error: ‘O_CLOFORK’ undeclared here (not in a function) 2 | int const foo = O_CLOFORK; | ^~~~~~~~~