cc -pthread   -Wall -Wextra -Werror=implicit-function-declaration unistd/posix_close.c -o unistd/posix_close -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread  -lgdbm_compat -lintl -lnetwork -lbsd -latomic
unistd/posix_close.c: In function 'main':
unistd/posix_close.c:9:14: error: implicit declaration of function 'posix_close' [-Werror=implicit-function-declaration]
    9 |         if ( posix_close(0, POSIX_CLOSE_RESTART) < 0 )
      |              ^~~~~~~~~~~
unistd/posix_close.c:9:29: error: 'POSIX_CLOSE_RESTART' undeclared (first use in this function)
    9 |         if ( posix_close(0, POSIX_CLOSE_RESTART) < 0 )
      |                             ^~~~~~~~~~~~~~~~~~~
unistd/posix_close.c:9:29: note: each undeclared identifier is reported only once for each function it appears in
cc1: some warnings being treated as errors