autogenerate files using autoconf/automake.

These files are not VCS controlled, but available on releases.  To
help ease check-out -> build flow, add a script to run the commands
for autogenerating the build scripts.

autogen.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+# simplistic script to run after checkout
+
+aclocal && \
+autoheader && \
+autoconf && \
+automake -a -c