cc -pipe -O   -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations unistd/_POSIX_SYNC_IO.c -o unistd/_POSIX_SYNC_IO -D_POSIX_C_SOURCE=202405L  -lm -lpthread -lrt  -lrt -lcrypt
unistd/_POSIX_SYNC_IO.c:4:2: error: #error "_POSIX_SYNC_IO is not defined"
 #error "_POSIX_SYNC_IO is not defined"
  ^~~~~