Fixes compiler error when AggCanvas is enabled.
Fixes compiler error when AggCanvas is enabled.

Recently we removed some variables that were needed for AggCanvas ifdef'ed
code.

wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI