cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration spawn/posix_spawnattr_getschedparam.c -o spawn/posix_spawnattr_getschedparam -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread  -liconv
spawn/posix_spawnattr_getschedparam.c:16:16: error: call to undeclared function 'posix_spawnattr_getschedparam'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
   16 |         if ( (errno = posix_spawnattr_getschedparam(&attr, &schedparam)) )
      |                       ^
spawn/posix_spawnattr_getschedparam.c:18:16: error: call to undeclared function 'posix_spawnattr_setschedparam'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
   18 |         if ( (errno = posix_spawnattr_setschedparam(&attr, &schedparam)) )
      |                       ^
2 errors generated.