diff --git a/wordfreq_builder/Makefile b/wordfreq_builder/Makefile
index 206c432..626cf46 100644
--- a/wordfreq_builder/Makefile
+++ b/wordfreq_builder/Makefile
@@ -2,10 +2,6 @@ PYTHON = python
 
 all: build.ninja
 
-# make sure this package is in 'develop' mode and up to date
-wordfreq_builder.egg-info/PKG-INFO: setup.py
-	$(PYTHON) setup.py develop
-
 # build the Ninja file that will take over the build process
 build.ninja: rules.ninja wordfreq_builder/ninja.py wordfreq_builder/config.py wordfreq_builder.egg-info/PKG-INFO
 	$(PYTHON) -m wordfreq_builder.cli.build_deps rules.ninja > build.ninja
diff --git a/wordfreq_builder/rules.ninja b/wordfreq_builder/rules.ninja
index 12c0360..8303663 100644
--- a/wordfreq_builder/rules.ninja
+++ b/wordfreq_builder/rules.ninja
@@ -15,6 +15,11 @@
 # Variables
 DATA = ./data
 
+# How to build the build.ninja file itself. (Use the Makefile to get it the
+# first time.)
+rule build_deps
+  command = python -m wordfreq_builder.cli.build_deps $in > $out
+
 # Splits the single file $in into $slices parts, whose names will be
 # $prefix plus a two-digit numeric suffix.
 rule split