Errors while compiling source

OS type: Mac OS X 10.11.6
List of errors:
qemu-io-cmds.c:837:5: warning: implicit declaration of function 'clock_gettime' is invalid in C99 [-Wimplicit-function-declaration]
    clock_gettime(CLOCK_MONOTONIC, &t1);
    ^
qemu-io-cmds.c:837:19: error: use of undeclared identifier 'CLOCK_MONOTONIC'
    clock_gettime(CLOCK_MONOTONIC, &t1);
                  ^
qemu-io-cmds.c:843:19: error: use of undeclared identifier 'CLOCK_MONOTONIC'
    clock_gettime(CLOCK_MONOTONIC, &t2);
                  ^
qemu-io-cmds.c:970:19: error: use of undeclared identifier 'CLOCK_MONOTONIC'
    clock_gettime(CLOCK_MONOTONIC, &t1);
                  ^
qemu-io-cmds.c:972:19: error: use of undeclared identifier 'CLOCK_MONOTONIC'
    clock_gettime(CLOCK_MONOTONIC, &t2);
                  ^
qemu-io-cmds.c:1184:19: error: use of undeclared identifier 'CLOCK_MONOTONIC'
    clock_gettime(CLOCK_MONOTONIC, &t1);
                  ^
qemu-io-cmds.c:1194:19: error: use of undeclared identifier 'CLOCK_MONOTONIC'
    clock_gettime(CLOCK_MONOTONIC, &t2);
                  ^
qemu-io-cmds.c:1306:19: error: use of undeclared identifier 'CLOCK_MONOTONIC'
    clock_gettime(CLOCK_MONOTONIC, &t1);
                  ^
qemu-io-cmds.c:1308:19: error: use of undeclared identifier 'CLOCK_MONOTONIC'
    clock_gettime(CLOCK_MONOTONIC, &t2);
                  ^
qemu-io-cmds.c:1351:19: error: use of undeclared identifier 'CLOCK_MONOTONIC'
    clock_gettime(CLOCK_MONOTONIC, &t2);
                  ^
qemu-io-cmds.c:1383:19: error: use of undeclared identifier 'CLOCK_MONOTONIC'
    clock_gettime(CLOCK_MONOTONIC, &t2);
                  ^
qemu-io-cmds.c:1518:19: error: use of undeclared identifier 'CLOCK_MONOTONIC'
    clock_gettime(CLOCK_MONOTONIC, &ctx->t1);
                  ^
qemu-io-cmds.c:1663:23: error: use of undeclared identifier 'CLOCK_MONOTONIC'
        clock_gettime(CLOCK_MONOTONIC, &ctx->t1);
                      ^
qemu-io-cmds.c:1885:19: error: use of undeclared identifier 'CLOCK_MONOTONIC'
    clock_gettime(CLOCK_MONOTONIC, &t1);
                  ^
qemu-io-cmds.c:1887:19: error: use of undeclared identifier 'CLOCK_MONOTONIC'
    clock_gettime(CLOCK_MONOTONIC, &t2);
                  ^
1 warning and 14 errors generated.
make: *** [qemu-io-cmds.o] Error 1