Update to 1.5.5
Rework the DEJAVU option to actually work. 
Before this commit rrdtool
depends on x11-fonts/dejavu if that port is already installed, but not
otherwise, and this sort of implicit dependencies are bad.
Make the DEJAVU option default to on. If cairo and pango are built without
X11 support, please consider disabling this option to avoid pulling in large
parts of X11
Remove the JSON option. This is a third party patch that doesn't apply any
more. Feel free to port it to this version of RRDTool.
Discussed with: marino 
PR: 205883 
Submitted by: marino