clang -O2  -Wall -Wextra timespec_get.c -o timespec_get -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm  -lintl
timespec_get.c:10:15: warning: implicit declaration of function 'timespec_get' is invalid in C99 [-Wimplicit-function-declaration]
        int result = timespec_get(&ts, TIME_UTC);
                     ^
timespec_get.c:10:33: error: use of undeclared identifier 'TIME_UTC'
        int result = timespec_get(&ts, TIME_UTC);
                                       ^
timespec_get.c:13:17: error: use of undeclared identifier 'TIME_UTC'
        if ( result != TIME_UTC )
                       ^
1 warning and 2 errors generated.