title: checking ifeq for variable in makefile
body: <p>Following is not working, do you know why?</p>
  
  <p>Note: CURRENT_CLUSTER is not 'my-local-cluster' and stil fails.</p>
  
  <pre><code>check-env:
      ifeq ($(CURRENT_CLUSTER), 'my-local-cluster')
          $(error CURRENT_CLUSTER is local $(CURRENT_CLUSTER), should be production cluster)
      endif
  </code></pre>