While it's nice having the shiny new lwIP stack, there is definitely
merit in being able to choose between two different network stacks. We
want to keep the legacy network stack around as it is known to handle
funky BIOS implementations and provides a good reference point when
bugs are suspected in the lwIP code.

Users now have a choice of .0 files. pxelinux.0 uses the legacy
network stack, while lpxelinux.0 uses lwIP.

Note that not every protocol is converted to using this new API. The
http, ftp and tcp code is still inherently tied to the netconn API,
and is only available with lpxelinux.0 and the lwIP stack. It's
unlikely that this code will ever be fixed up to work with the legacy
network stack.

Network stack operations are abstracted behind the net_core_*
interface, and each network stack has private data fields contained
within a struct net_private.

Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Gene Cumm <gene.cumm@gmail.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Signed-off-by: Gene Cumm <gene.cumm@gmail.com>

16-bit COMBOOT files are no longer supported by Syslinux in 5.00 so
delete all references and change any 32-bit COMBOOT image references
to mention ELF instead.

Some of the COMBOOT stuff is still used internally so we can't nuke
core/comboot.inc yet, but that will disappear in a future release.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>

This is a partial revert of commit b26d1c8642a8 ("Clean up $(GPLLIB)
leak"). While we do need to use $(C_LIBS) and respect $(NOGPL), we
should also be distributing libcom32gpl.c32. Now that we have ELF
modules, such as hdt.c32, that need to have some of their symbols
dynamically resolved at runtime we need to distribute libcom32gpl.c32.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>

We need to install libmenu.c32 as it is required by modules like
hdt.c32.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Modules were linking against com32/gpllib/libcom32gpl.c32 even when
NOGPL was set, so remove it from various modules Makefiles and use
$(C_LIBS) in mk/elf.mk which already has the conditional-magic for
$(GPLLIB).

Also, the object files in com32/gpllib/ are not distributed in the
release tarballs, which means that if a user does a 'make netinstall'
they hit the following install error,

	install: cannot stat `com32/gpllib/*.c32': No such file or directory

Add a $(INSTALLABLE_MODULES) variable to separate the list of build
and install modules.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Some Makefiles were still referring to libutil_com.a, even though we
stopped producing that file with commit 74518b8b691c ("elflink: Make
ELF the default object format"). Delete all references to avoid the
following install error,

	install: cannot stat `libutil_com.a': No such file or directory

Remove the install target from com32/elflink as we no longer build any
of the test modules, and so don't need to install them.

Also, we need to add ldlinux.c32 to the list of modules that *must* be
installed for all targets, since it is required for Syslinux to
function correctly.

Reported-by: Dag Wieers <dag@wieers.com>
Reported-by: Michael D. Setzer II <mikes@kuentos.guam.net>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

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

A lot of development has gone on in the 'master' branch since the last
time we merged; new features, bug fixes, etc, etc.

Conflicts:
	Makefile
	com32/Makefile
	com32/lib/Makefile
	com32/lib/syslinux/load_linux.c
	com32/modules/Makefile
	com32/modules/chain.c
	core/bootsect.inc
	core/init.inc
	version

We need the library modules to be added to MODULES.

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