Merge the SYSLINUX and EXTLINUX patching code and core code, removing
EXTLINUX as a separate derivative.  All the disk-based systems now use
the same code.

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

Fix mishandling of the null pathname case in the syslinux installer,
and generally clean up the handling of the subpath name.

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

Put all the Linux ioctl header magic into a single shared file, and
try to make it as generally useful as possible.

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

Switch to consistent use of 64-bit sector pointers; this should enable
booting even for individual *partitions* larger than 2 TB.  In order
to not slow down the boot too much, switch the initial load from an
enumeration to an extent map.  This means the table gets larger (since
we have to assume the worst case), but it simplifies the Sector 1 code
(since we can push all the hard stuff into the installer), and will
speed up booting in the general case.

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

When installing into the root directory, we should logically search
the root directory first.  Thus, we need to make sure the current path
is "/" not "".

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

Provide for backwards command-line compatibility, together with
warning messages where appropriate.

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

-o has been supported for a very long time; recommend using -t
instead, but for now proceed with an error message.

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

The previous merging extlinux/syslinux patch is not sufficient, the
syslinux is not real "patchbased", hence:

* fill currentdir in patcharea
* search "extlinux.conf" and "syslinux.cfg" for generic_load_config
* define boot_image and boot_sector macro for ldsyslinux
  this could make further merging extlinux and syslinux possible

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

Thus we can share same command line options and reduce a lot of dup
code...

Seems like a big patch, but the changes are quite safe, no much logical
change.

Signed-off-by: Alek Du <alek.du@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

CLean up warnings in the installers.

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