Fix mangled SVN keyword.

LWIP_NOASSERT is tested with #ifdef, not #if. Drop it its incorrect definition from lwipopts.h and instead disable it in the Makefile for release, profile and kprofile builds.

def_vbox_lwip_flags: Make it possible to supply additional compilation flags to lwip from the client component by adding FOO_LWIP_INCS to corresponding _INCS, ditto for _DEFS. This is intended for components that use def_vbox_lwip_private and then call def_vbox_lwip_flags on a few of its files that use lwip. Adjust affected callers. Not used by any component yet, but it makes it possible to supply different lwipopt.h to different builds of lwip (coming soon in a separate commit).

Minor cosmetics, no functional change.

Do not hardcode lwip location in lwip makefile. Provide functions for "calling" makefiles to add lwip to its sources and use these functions in Devices and NAT. XXX: It's still icky that Devices pulls in lwip makefile and then NAT (which is included later) inherits it. But this commit allows inclusion problem (and possible move of the lwip directory) to be addressed separately.

Move Devices bits to Devices makefile.

Move slip, ppp and snmp sources to separate += assignments and comment them out - we don't enable these features in lwipopts.h.

Drop src/netif/ethernetif.c from LWIP_SOURCES - it's an #if 0'ed sample code.

Minor cosmetic in variable assignments.

VBoxLwipCore.cpp is a generic wrapper for lwip, so it should live alongside lwip. This removes Devices/Network from the list of mandatory include directories (this will be necessary for component specific lwipopts.h).

Move proxy sources from Devices/Network/lwip-new/vbox to NetworkServices/NAT where they belong.

export lwip-new to OSE