diff --git a/build/concurrent-ruby-ext/1.2.1 b/build/concurrent-ruby-ext/1.2.1
new file mode 100644
index 00000000..e69de29b
diff --git a/build/concurrent-ruby-ext/1.2.2 b/build/concurrent-ruby-ext/1.2.2
new file mode 100644
index 00000000..e69de29b
diff --git a/build/raindrops/0.20.1 b/build/raindrops/0.20.1
new file mode 100644
index 00000000..d72115ab
--- /dev/null
+++ b/build/raindrops/0.20.1
@@ -0,0 +1 @@
+EXTRA_PKGS="linux-headers"