configure: Use LT_INIT from libtool 2 instead of deprecated AC_PROG_LIBTOOL
AC_PROG_LIBTOOL was replaced by LT_INIT in libtool 2 in 2008, so it's time to rely on it.
Clears autoconf warnings:
configure.ac:20: warning: The macro `AC_PROG_LIBTOOL' is obsolete. configure.ac:20: You should run autoupdate. m4/libtool.m4:100: AC_PROG_LIBTOOL is expanded from... configure.ac:20: the top level
Signed-off-by: Alan Coopersmith alan.coopersmith@oracle.com