As an FYI, ATrpms just posted Exim 4.80.1 RPM binary packages for currently supported RedHat, CentOS and Scientific Linux versions RHEL4, RHEL5 and RHEL6.  The RPMs are available here:

http://dl.atrpms.net/

I have so far installed the these RPMs on four 32bit CentOS5 systems and everything appears to be working properly.

FYI,

Gordon