Add a --one-filesystem option to getfacl.  With this option, getfacl will not
cross mount points, similar to "tar --one-file-system".

(Patch modified by Andreas Gruenbacher.)

Move #include "config.h" from misc.h to every source file.  It's incorrect
to include it after a system header file because it does things like:

Those must come before you include any system header file in order for
them to work properly.  It hasn't bitten us so far, but we still should
fix the files to do the right thing.

Make the conditional easier to read.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

The octal unquote code can't handle escaping backslashes except by
specifying the octal code for the backslash.  That's not exactly a
user-friendly interface for a scenario that may not be that uncommon.
The unquote code isn't documented in the man page and can result in
confusion when specifying names via a Windows domain that are entirely
numeric (e.g. WINDOM\1234).

This patch adds handling to allow literal escaping of the backslash (\\)
as both input and output and documents the quoting rules in the setfacl
man page.  Also included are test cases for escaped backslashes followed
by letters, escaped backslashes followed by numbers, and the original
use case of escaped character literals.

[Minor fixes by Andreas Gruenbacher.]

walk_tree.c internal variables should not be exposed to libmisc users.

When static linking libacl, people sometimes run into symbol collisions
because their own code defines symbols like "quote".  So for acl internal
symbols, use an __acl_ prefix.