cc -O2 -pipe -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations fcntl/S_ISVTX.c -o fcntl/S_ISVTX -D_POSIX_C_SOURCE=202405L  -lm -lpthread -lrt  -lstdthreads -lcrypt
fcntl/S_ISVTX.c:9:2: error: "S_ISVTX is not defined"
    9 | #error "S_ISVTX is not defined"
      |  ^
1 error generated.