title: Difference between "include" and "-include" in a makefile
body: <p>In a makefile, what is the difference in meaning between <code>include</code> and <code>-include</code>?</p>
  
  <p>Examples:</p>
  
  <pre><code>-include $(APPINCLUDES)
  
  include $(CONTIKI)/platform/$(TARGET)/Makefile.$(TARGET)
  </code></pre>