Duh, don't include .rbc files in the gem.

paperclip.gemspec

@@ -4,7 +4,7 @@ require 'paperclip/version'
 include_files = ["README*", "LICENSE", "Rakefile", "init.rb", "{lib,tasks,test,rails,generators,shoulda_macros}/**/*"].map do |glob|
   Dir[glob]
 end.flatten
-exclude_files = ["test/s3.yml", "test/debug.log", "test/paperclip.db", "test/doc", "test/doc/*", "test/pkg", "test/pkg/*", "test/tmp", "test/tmp/*"].map do |glob|
+exclude_files = ["**/*.rbc", "test/s3.yml", "test/debug.log", "test/paperclip.db", "test/doc", "test/doc/*", "test/pkg", "test/pkg/*", "test/tmp", "test/tmp/*"].map do |glob|
   Dir[glob]
 end.flatten