On Mac OS X, libtool and libtoolize are named glibtool and glibtoolize to prevent conflicts with the system's libtool program which does something different. autogen.sh should be aware of this and attempt to use glibtoolize if on the Mac, or perhaps if libtoolize doesn't exist.
A relevant thread for another project:
I didn't quite understand the conclusion..
This looks like an OK fix to me for now:
libtoolize --force || glibtoolize --force || exit $?
Created attachment 18702 [details]
Landed in r29807.