Always looking for the latest and greatest code for AVR, I scan the debian Sid repositories every few months for updated packages to use. Recently debian Sid included the latest gcc-avr 4.8 package, binutils-avr and the new avrdude 6.0.1 package. So I had to install them all to test.
The new avrdude 6.0.1 is the first release in two years, so it has a lot of good stuff, including a fix for the long standing chip delay bug affecting the AVRmega1284p used in the Goldilocks and Pololu SVP platforms.
Unfortunately, there is a new device format used in the avrdude.conf file which breaks the standard Eclipse AVR Plugin, rendering the MCU choice ineffective.
Asking a question on avrfreaks.net found the answer. keestux has fixed the problem and has released an interim AVR Plugin 2.4.1 which incorporates a fix for the change in avrdude.conf file format.
keestux Eclipse AVR Plugin 2.4.1 is at: http://www.ijzerbout.nl/avr-eclipse/updatesite
Add his update site to your software sources, and life is good again.