diff --git a/Makefile b/Makefile
index f9575bb..3f08f63 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ ENTRY=-main
 
 .PHONY: $(OUT)
 $(OUT): clean
-	sbcl --load build-executable.lisp
+	sbcl --load build-asteroid.lisp
 
 quicklisp-manifest.txt: *.asd
 	sbcl --non-interactive \
diff --git a/build-executable.lisp b/build-asteroid.lisp
similarity index 80%
rename from build-executable.lisp
rename to build-asteroid.lisp
index a4dd448..1d45b31 100755
--- a/build-executable.lisp
+++ b/build-asteroid.lisp
@@ -1,5 +1,15 @@
 ;; -*-lisp-*-
 
+(unless *load-pathname*
+  (error "Please LOAD this file."))
+
+(when (find-package :quicklisp)
+  (error "Please run this file as a script or from the Makefile."))
+
+(defpackage #:asteroid-bootstrap
+  (:use #:cl)
+  (:export #:*root* #:path))
+
 ;; we require quicklisp to load our transitive dependencies.
 (load "~/quicklisp/setup.lisp")