The fedora updates repository for Fedora 15 has newer versions of avr-gcc and avr-gcc-c++
than are available for Fedora 14. Namely 4.6.1-2 for Fedora 15 as compared to 4.5.3-1 for Fedora 14.
These showed up 9-1-2011 on our mirror. Unfortunately I cannot test them on the machine
I am using for arduino development as it is a Fedora 14 machine and trying to install the
Fedora 15 packages there fails due to library dependencies. The folks that reported this
problem for Fedora 15 ought to do a yum update and try again and let us know if this version
fixes this problem.
Fedora 16 is in alpha, so Fedora 14 will soon be end of life if it isn't already, so I don't hold
out much hope that this will find its way into Fedora 14 updates (and I guess I should get ready
to upgrade my home system, probably to 16).