That function is meant more for user programs, and should still be rarely used, since it's not portable.
Instead, we already know the number of arguments. We just call __lc_fast_syscallN, which also sets errno.
read() and close() are in unistd.h, but open() in fnctl.h.
I thought only the definitions for O_SOMETHING were in fnctl.h, but it is as it is.
Don't know why, but let's not anger the Unix gods.
The FILE* C API is pending as well.
