Add a new macro "alignz" to align with zero bytes; use to align inside
a data section (i.e. a progbits section which doesn't contain code.)

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

cmdline.inc: Unbreak "make depend"
Makefile: fix "make spotless"

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

ipappend information is needed for the plain cmdline too, since it may
be used by linux.c32.  While we're at it, clean up the handling of
ipappend lines -- we can rather obviously use a loop for them.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Move source files out of the root directory; the root is a mess and
has become virtually unmaintainable.  The Syslinux core now lives in
core/; the Linux and generic utilities has moved into utils/, and
copybs.com has moved into dos/; it had to go somewhere, and it seemed
as good a place as any.