autoconf: Add autogen.sh, remove configure and config.h.in

Put autoconf-generated files in the release tarball.

The minimum required version of autoconf is currently 2.69.

If version 2.69 or later is already installed and there is no
autoconf default, it may be necessary to set the AUTORECONF
environment variable to enable the one to use, like:
AUTORECONF=autoreconf-2.69 ./autogen.sh
or
AUTORECONF=autoreconf-2.71 ./autogen.sh

1 files changed, 21 insertions, 4 deletions

diff --git a/INSTALL.md b/INSTALL.md
index b3fbf42e..22df2637 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -12,9 +12,27 @@ the generally available GNU C compiler (GCC) or Clang.
 
 After libpcap has been built (either install it with `make install` or
 make sure both the libpcap and tcpdump source trees are in the same
-directory), run `./configure` (a shell script). `configure` will
+directory), do the following steps:
+
+* If you build from a git clone rather than from a release archive,
+run `./autogen.sh` (a shell script). The autogen.sh script will
+build the `configure` and `config.h.in` files.
+
+On some system, you may need to set the `AUTORECONF` variable, like:
+`AUTORECONF=autoreconf-2.69 ./autogen.sh`
+to select the `autoreconf` version you want to use.
+
+* Run `./configure` (a shell script). The configure script will
 determine your system attributes and generate an appropriate `Makefile`
-from `Makefile.in`.  Now build tcpdump by running `make`.
+from `Makefile.in`.  The configure script has a number of options to
+control the configuration of tcpdump; `./configure --help` will show
+them.
+
+* Next, build tcpdump by running `make`.
+
+On OpenBSD, you may need to set, before the `make`, the `AUTOCONF_VERSION`
+variable like:
+`AUTOCONF_VERSION=2.69 make`
 
 If everything builds ok, `su` and type `make install`.  This will install
 tcpdump and the manual entry.  Any user will be able to use tcpdump to
@@ -62,15 +80,14 @@ ascii_strcasecmp.c - locale-independent case-independent string comparison
 		routines
 atime.awk	- TCP ack awk script
 atm.h		- ATM traffic type definitions
+autogen.sh	- build configure and config.h.in (run this first)
 bpf_dump.c	- BPF program printing routines, in case libpcap doesn't
 		  have them
 chdlc.h		- Cisco HDLC definitions
 cpack.c		- functions to extract packed data
 cpack.h		- declarations of functions to extract packed data
 config.guess	- autoconf support
-config.h.in	- autoconf input
 config.sub	- autoconf support
-configure	- configure script (run this first)
 configure.ac	- configure script source
 doc/README.*	- some building documentation
 ethertype.h	- Ethernet type value definitions