cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration threads/thrd_exit.c -o threads/thrd_exit -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread  -liconv
threads/thrd_exit.c:3:10: fatal error: 'threads.h' file not found
    3 | #include <threads.h>
      |          ^~~~~~~~~~~
1 error generated.