No C++/C99-style comments; not all C compilers necessarily support them.
Clean up handling of -g and -O flags.

AC_PROG_CC adds -g and -O2 to CFLAGS if you're using GCC; don't bother
adding either of them, or -O, ourselves if we're using GCC.

Add -O for all non-GCC compilers.
Note that clang, for example, is considered "gcc" by autoconf.
We require autoconf 2.61 in configure.in; that suffices.

Don't say "we require 2.50" in various macros.
With .devel, add -g3 for MIPS C and DEC C.

Lifted from the libpcap configure script, which adds -g even without
.devel, presumably so that programs linked with libpcap can get
debugging symbols.

Those compilers are for dead OSes (IRIX, Tru64 UNIX); we should probably
do whatever voodoo is needed to get Sun^WOracle C, IBM's C compiler for
AIX, and HP C to build optimized with debug symbols.
We no longer use the GCC version, so don't fetch it.

Fix some indentation while we're at it.
Update a comment for the previous commit.
Explain why we set -xansi -signed for MIPS C.
Babel: improve printing of time intervals

All Babel intervals are encoded in centiseconds and must not be 0. In an
Update TLV the interval value 0xFFFF means infinity (RFC6126 Section
4.4.9). Update the test cases.
adopt MacOS deprecation workaround from FreeRADIUS

A MacOS build of tcpdump used to produce deprecation warnings on OpenSSL
function calls. Alan DeKok explained that this is the effect of Apple's
modifications to OpenSSL and that the very same problem has already been
solved in FreeRADIUS server source code with pre-processor macros.

Copy the macros into tcpdump header file and make use of them around the
functions that call OpenSSL functions.
print-tcp: separate tcp_seq_hash into ipv4 and ipv6 versions

This cleans up and removes some duplicate code. The ipv4 and ipv6 versions of
the codepath are virtually identical now save for the variable types.
Put lower-case letters before their upper-case equivalents in getopt().

For consistency - V came before v, unlike all other options.
Merge branch 'master' of git+ssh://bpf.tcpdump.org/tcpdump/master/git/tcpdump
Add -g3 on some platforms even if .devel isn't present.

Now that we're requiring autoconf 2.61 or later, AC_PROG_CC sets -g
along with -O2 for GCC-like compilers regardless of whether .devel is
present.  Add "include debugging symbols" options for MIPS C/DEC C
regardless of whether .devel is present; that's -g3, which is the
version that doesn't turn optimization off (we also turn on -O).

Also, don't change the ABI on IRIX depending on .devel.

I'm not sure why we were doing that; if somebody has a good reason to
continue doing it, please let us know what it is.

Expand some comments while we're at it.
fix flags printing tests

The test cases included the timestamp (due to missing -t) and failed
unless run in the same timezone as produced. The failures printed by
print-flags.sh did not make it into the final report because the script
always returned 0.

Strip the timestamps and replace print-flags.sh with some contents in
TESTLIST.
fix printing of unknown TCP options

TCP options decoder would mix decimal and hexadecimal digits when
printing an unknown option. For example, the pre-TFO revision would
print TFO as follows:
[Unknown Option 254f989090909090000]

Refine output format to print the same data as follows:
[unknown-254 0xf989090909090000]
print-nfs: add versions of nfsreq_print and nfsreply_print that do not print dst/src addresses
print-tcp: move nfs specific dispacting to after the tcp header decoding