`timespec_get` and `timespec_getres` are both C23 functions. They're
similar to the POSIX functions `clock_gettime` and `clock_getres`, but
both sets of functions define extra, exclusive features. I didn't
implement the extra features yet, partially because Redox doesn't seem
to support them yet either.
This will allow us to redefine the exit function.
For example:
```
#define exit(code) { \
fprintf(stderr, "%s:%d: exit(%s) in function ‘%s’\n",
__FILE__, __LINE__, #code, __func__); \
_exit(code); \
}
```
Josh Megnauth