1) Simplify the manpage. Just refer to fallocate(2) and stop trying
to list supported file systems. This can change and everbody
with common sense can bring up the relevant manpages of a given
operating system himself.
Use the num-semantics.
2) Use estrtonum() instead of estrtol().
3) Allow multiple arguments.
For the common case where we have pts/ or tty do it straight
away. Otherwise traverse /dev for a match. This fixes ps(1) when
it is executed over a serial terminal with tty names like ttyAMA0.
