cc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations unistd/sync.c -o unistd/sync -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lintl -liconv
unistd/sync.c:11:21: error: ‘sync’ undeclared here (not in a function); did you mean ‘fsync’?
   11 | void (*foo)(void) = sync;
      |                     ^~~~
      |                     fsync