Commit 518eaeca38dfc6f840907f6bcc1ce28826801888 Parent 3307a5ac1d2819ecbde0763aef3102828e13ae44 Author John MacFarlane <jgm@berkeley.edu> Date Wed, 24 Sep 2014 22:22:51 -0700 Makefile: Use ?= so variables can be set on command line.