cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration spawn/posix_spawnattr_getschedpolicy.c -o spawn/posix_spawnattr_getschedpolicy -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread  -liconv
spawn/posix_spawnattr_getschedpolicy.c:15:16: error: call to undeclared function 'posix_spawnattr_getschedpolicy'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
   15 |         if ( (errno = posix_spawnattr_getschedpolicy(&attr, &schedpolicy)) )
      |                       ^
spawn/posix_spawnattr_getschedpolicy.c:15:16: note: did you mean 'posix_spawnattr_getsigdefault'?
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/spawn.h:93:9: note: 'posix_spawnattr_getsigdefault' declared here
   93 | int     posix_spawnattr_getsigdefault(const posix_spawnattr_t * __restrict,
      |         ^
spawn/posix_spawnattr_getschedpolicy.c:17:16: error: call to undeclared function 'posix_spawnattr_setschedpolicy'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
   17 |         if ( (errno = posix_spawnattr_setschedpolicy(&attr, schedpolicy)) )
      |                       ^
2 errors generated.