Was rebuilding FreeSWITCH source and had upgraded my test machine Ubuntu from 14.10 to version 15.04 so I did a make uninstall on FreeSWITCH and reran the bootstrap.sh but it came up with the error of libtool not found.

Libtool (2.4.2) was installed but what I found is that I had to add libtool-bin with,

sudo apt-get install libtool-bin

Then bootstrap.sh worked fine.