libtool version mismatch

Building ec2new on CentOS 6.2, I came across the following error:

libtool: Version mismatch error.  This is libtool 2.4, but the
libtool: definition of this LT_INIT comes from libtool 2.2.6b.
libtool: You should recreate aclocal.m4 with macros from libtool 2.4
libtool: and run autoconf again.

I found references to LT_INIT in ltmain.sh, so I deleted it and ran libtoolize.  After that the build process suggested in INSTALL worked fine.