Modernise autoconf code to use modern archive macros.

--- a/configure.in
+++ b/configure.in
@@ -1,7 +1,7 @@
 AC_INIT(snpfile, 2.0.1, mailund@birc.au.dk)
 AM_INIT_AUTOMAKE
 AC_CONFIG_MACRO_DIR([m4])
-AM_CONFIG_HEADER(config.hh)
+AC_CONFIG_HEADERS([config.hh])
 
 LT_INIT
 AC_PROG_CXX
@@ -14,18 +14,9 @@
 fi
 AC_DEFINE_UNQUOTED(PREFIX, "$thePREFIX", [Installation prefix])
 
-AX_BOOST([1.33.1],,
-AC_ERROR([[
-************************************************************************
-************************************************************************
-The Boost library was not found on this system.  We use this library
-extensively, and cannot proceed without it.  You can obtain it from
-<http://www.boost.org>.
-************************************************************************
-************************************************************************
-]])
-)
-
+AX_BOOST_BASE([1.33.1])
+AX_BOOST_PROGRAM_OPTIONS
+AX_BOOST_SIGNALS
 
 AC_OUTPUT([
 	Makefile