cc -pthread   -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations spawn/POSIX_SPAWN_SETPGROUP.c -o spawn/POSIX_SPAWN_SETPGROUP -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt  -lintl -liconv
spawn/POSIX_SPAWN_SETPGROUP.c:2:10: fatal error: spawn.h: No such file or directory
    2 | #include <spawn.h>
      |          ^~~~~~~~~
compilation terminated.