clang -O2  -Wall -Wextra -Werror=implicit-function-declaration aio/aio_fsync.c -o aio/aio_fsync -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm  -lintl
aio/aio_fsync.c:6:10: fatal error: 'pthread.h' file not found
#include <pthread.h>
         ^
1 error generated.