[plt-scheme] Patch for truncate(2)/chsize

At Wed, 29 Jun 2005 09:39:04 -0600, Evan Farrer wrote:
> I've created a patch for plt/collects/mzlib/os.ss that provides ffi access
> to truncate(2).

This patch has been applied, but I modified it to assume that
ftruncate() accepts a long-long second argument. This assumption is
correct for OS X, and I think it's safe for little-endian machines.
Callers beware.

(I also added a call to scheme_security_check_file, so that security
guards are notified about the attempt.)

Matthew