cc -pthread   -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations unistd/_POSIX_FALLOC.c -o unistd/_POSIX_FALLOC -D_POSIX_C_SOURCE=202405L  -lm -lpthread   -liconv
unistd/_POSIX_FALLOC.c:4:2: error: "_POSIX_FALLOC is not defined"
    4 | #error "_POSIX_FALLOC is not defined"
      |  ^
1 error generated.