Someone

checking for exo-0.3 >= 0.3.1.2... found, but
*** The required package exo-0.3 was found on your system,
*** but the installed version () is too old.
*** Please upgrade exo-0.3 to atleast version 0.3.1.2, or adjust
*** the PKG_CONFIG_PATH environment variable if you installed
*** the new version of the package in a nonstandard prefix so
*** pkg-config is able to find it.