This patch adds the g_strlcpy and g_strlcat functions to glib
to support safe manipulation of fixed-length string buffers.
These functions were originally developed by Todd Miller
(under the names strlcpy and strlcat).
They are available on many (but not all) Unix-like systems (such as
OpenBSD, FreeBSD, and Solaris); see
ftp://ftp.openbsd.org/pub/OpenBSD/src/lib/libc/string/strlcpy.3 and
http://www.openbsd.org/security.html.

This version detects if there's a strlcpy/strlcat on the system, and
if so, calls it (i.e. it's a wrapper), otherwise, it provides
an implementation.

I posted this patch to the mailing list & have received no
negative feedback.  This patch I'm sending does have one minor
change, I changed all "char" to "gchar" to be consistent with
glib conventions.