rename/reformat documentation to markdown

Author: mcr

CONTRIBUTING renamed to CONTRIBUTING.md

@@ -258,19 +258,19 @@ ChmodBPF/*	- macOS startup item to set ownership and permissions
 CMakeLists.txt	- CMake file
 CONTRIBUTING	- guidelines for contributing
 CREDITS		- people that have helped libpcap along
-INSTALL.txt	- this file
+INSTALL.md	- this file
 LICENSE		- the license under which tcpdump is distributed
 Makefile.in	- compilation rules (input to the configure script)
-README		- description of distribution
-README.aix	- notes on using libpcap on AIX
-README.dag	- notes on using libpcap to capture on Endace DAG devices
-README.hpux	- notes on using libpcap on HP-UX
-README.linux	- notes on using libpcap on Linux
-README.macos	- notes on using libpcap on macOS
-README.septel   - notes on using libpcap to capture on Intel/Septel devices
-README.sita	- notes on using libpcap to capture on SITA devices
-README.tru64	- notes on using libpcap on Digital/Tru64 UNIX
-README.Win32	- notes on using libpcap on Win32 systems (with WinPcap)
+README.md	- description of distribution
+doc/README.aix	- notes on using libpcap on AIX
+doc/README.dag	- notes on using libpcap to capture on Endace DAG devices
+doc/README.hpux	- notes on using libpcap on HP-UX
+doc/README.linux.md - notes on using libpcap on Linux
+doc/README.macos	- notes on using libpcap on macOS
+doc/README.septel   - notes on using libpcap to capture on Intel/Septel devices
+doc/README.sita	- notes on using libpcap to capture on SITA devices
+doc/README.tru64	- notes on using libpcap on Digital/Tru64 UNIX
+doc/README.Win32	- notes on using libpcap on Win32 systems (with WinPcap)
 VERSION		- version of this release
 acconfig.h	- support for post-2.13 autoconf
 aclocal.m4	- autoconf macros

INSTALL.txt renamed to INSTALL.md

@@ -2,14 +2,17 @@ To report a security issue please send an e-mail to security@tcpdump.org.
 
 To report bugs and other problems, contribute patches, request a
 feature, provide generic feedback etc please see the file
-CONTRIBUTING in the libpcap source tree root.
+[CONTRIBUTING](CONTRIBUTING.md) in the libpcap source tree root.
+
+The directory doc/ has README files about specific operating systems and
+options.
 
 LIBPCAP 1.x.y
 Now maintained by "The Tcpdump Group"
 https://www.tcpdump.org
 
 Anonymous Git is available via:
-	git clone git://bpf.tcpdump.org/libpcap
+        https://github.com/the-tcpdump-group/libpcap.git
 
 formerly from 	Lawrence Berkeley National Laboratory
 		Network Research Group <libpcap@ee.lbl.gov>
@@ -67,9 +70,10 @@ kernel source and/or object patches available in:
 
 	https://www.tcpdump.org/other/bpfext42.tar.Z
 
-Linux, in the 2.2 kernel and later kernels, has a "Socket Filter"
-mechanism that accepts BPF filters; see the README.linux file for
-information on configuring that option.
+Linux has a number of BPF based systems, and libpcap does not support
+any of the eBPF mechanisms as yet, although it supports many of the
+memory mapped receive mechanisms.
+See the [README.linux](doc/README.linux.md) file for more information.
 
 Note to Linux distributions and *BSD systems that include libpcap: