cc -O2 -pipe -pthread  -Wall -Wextra -Werror=implicit-function-declaration spawn/posix_spawn_file_actions_addfchdir.c -o spawn/posix_spawn_file_actions_addfchdir -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread -lrt  -lstdthreads -lcrypt
spawn/posix_spawn_file_actions_addfchdir.c:44:16: error: call to undeclared function 'posix_spawn_file_actions_addfchdir'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
   44 |         if ( (errno = posix_spawn_file_actions_addfchdir(&actions, dirfd)) )
      |                       ^
spawn/posix_spawn_file_actions_addfchdir.c:44:16: note: did you mean 'posix_spawn_file_actions_addfchdir_np'?
/usr/include/spawn.h:92:5: note: 'posix_spawn_file_actions_addfchdir_np' declared here
   92 | int posix_spawn_file_actions_addfchdir_np(posix_spawn_file_actions_t *,
      |     ^
1 error generated.