Use Libtool and -R to encode run paths.

Use Libtool and -R to encode run paths.

	* README: Mention the dependencies more clearly near the beginning.
	Add a step to use Libtool if it's not already used.
	* build-aux/boost.m4 (BOOST_FIND_LIB): Add -R flags in the LDFLAGS
	and fix a bug when --with-boost isn't used which leads to
	$with_boost being empty which leads that /lib is checked first.
	* configure.ac: Invoke AC_PROG_LIBTOOL.
	* tests/testsuite.at (AT_CONFIGURE_AC): Import the content of
	aclocal.m4 without the m4_include's in order to use AC_PROG_LIBTOOL
	without getting the hassle of libtoolize.
	(AT_CHECK_MACRO): Do not pass -W obsolete to autoconf to avoid
	spurious warnings due to Libtool.

Signed-off-by: Benoit Sigoure <tsuna@lrde.epita.fr>