that is the error message:
checking for sasl/sasl.h... no
Please install SASL to continue. The package is called libsasl2-dev on Ubuntu and cyrus-sasl on Gentoo.
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.
Provided configuration options:
extconf failed, exit code
It clearly states that some library is missing
Please install SASL to continue. The package is called libsasl2-dev on Ubuntu and cyrus-sasl on Gentoo. *** extconf.rb failed ***
For Ubuntu you have to install those
sudo apt-get install libsasl2 sudo apt-get install libsasl2-dev