cc -O2 -pipe  -pthread  -Wall -Wextra -Werror=implicit-function-declaration threads/mtx_unlock.c -o threads/mtx_unlock -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread 
threads/mtx_unlock.c:3:10: fatal error: 'threads.h' file not found
#include <threads.h>
         ^~~~~~~~~~~
1 error generated.