makefs: make the buffer functions look exactly like the kernel ones

[emaste]

Summary

From NetBSD

make the buffer functions look exactly like the kernel ones and add other
cruft to make the kernel files compile.

ffs.c 1.54
ffs/buf.c 1.13
ffs/buf.h 1.3
ffs/ffs_alloc.c 1.21
ffs/ffs_balloc.c 1.15

https://github.com/jsonn/src/commit/03dc6da80956f995c02320b03d526a57400d24c3

[emaste]

This was in an old tree from an earlier attempt at updating makefs. It appears to be an incomplete port of the referenced NetBSD change.

http://mail-index.netbsd.org/source-changes/2013/01/26/msg040880.html

[marcel]

LGTM -- I don't think this will impact building makefs on non-FreeBSD...

[emaste]

In D8404#175008, @marcel wrote:

LGTM -- I don't think this will impact building makefs on non-FreeBSD...

Indeed, NetBSD builds makefs on all of their supported host platforms and my goal is to gradually sync to their version.