Replace data.sh for a Makefile?

[defvol]

Ref: https://github.com/rodowi/marco/blob/master/data.sh
Inspired by

• https://bost.ocks.org/mike/make/
• https://github.com/mbostock/world-atlas/blob/master/Makefile
• https://github.com/mbostock/us-atlas/blob/master/Makefile