[FIXUP] ... or do we?

This is the other option I guess... though, probably better that we just
use `bundle install` on CI, as it is only 3 seconds to do that.

Author: NickLaMuro

Rakefile

@@ -14,11 +14,16 @@ end
 # Ruby Extension
 # ==========================================================
 
-require 'rake/extensiontask'
-Rake::ExtensionTask.new('stackprof', GEMSPEC) do |ext|
-  ext.lib_dir = 'lib/stackprof'
+begin
+  require 'rake/extensiontask'
+  Rake::ExtensionTask.new('stackprof', GEMSPEC) do |ext|
+    ext.lib_dir = 'lib/stackprof'
+  end
+  task :build => :compile
+rescue LoadError => e
+  # rake-compiler not installed.  No problem if on CI.
+  raise e unless ENV["TRAVIS"]
 end
-task :build => :compile
 
 # ==========================================================
 # Testing