kmx.io/rbpkg

diff --git a/lib/rbpkg/repo.rb b/lib/rbpkg/repo.rb
index 4d47d2e..5e6bb07 100644
--- a/lib/rbpkg/repo.rb
+++ b/lib/rbpkg/repo.rb
@@ -42,7 +42,7 @@ class Rbpkg::Repo
   end
 
   def make_cmd
-    "${make} -j #{Rbpkg.ncpu}"
+    "#{make} -j #{Rbpkg.ncpu}"
   end
 
   def checkout(branch)