Only set MODP768_MODULUS with USE_VERYWEAK_DH1
Remove unused MD2_DIGEST_SIZE
Always assume UDPFROMTO works on Linux and BSD

- Phased out UDPFROMTO_DEFS
- Moved HAVE_UDPFROMTO, HAVE_IP_RECVDSTADDR and HAVE_IP_PKTINFO defines to arch
  specific sysdep.h versions of bsd and linux
- Fixes a bug where compiling just NETKEY and no KLIPS support would lose HAVE_UDPFROMTO
Log a warning for NETKEY/XFRM breaking RFC 4301, Section 5.2

When setting up a transport mode connection with a protoport selector,
the Linux NETKEY/XFRM stack will accept any encrpyted packets between
the hostpairs, and not just the ones covered by the selector. We log
a warning about this.
Sync patches with variables names

ESP_reserved -> ESP_RESERVED
IPCOMP_V42BIS -> IPCOMP_LZJH
Additional safety checks to addrtot(), inet_addrtot() and sin_addrtot()

These functions when used properly are bassed a char of size ADDRTOT_BUF
which is more then enough to strncat "<invalid>" into.  But scanning
tools don't know about these and show red flags in case something smaller
is passed.

So now we check if the dstlen passed in is smaller then sizeof("invalid")

At least if someone would call these functions with chars that are too
small, we just truncate the text "<invalid>".
Close socket fd of the interface in _iface_down()
Move the close() call for the sock to the function that created it.
Fix addrtot() with a passert and off-by-one