title: Makefile: Setting env var for one build step
body: <p>I'm using GNU make and Makefiles. Is it possible to set an environment variable for one build step?</p>
  
  <p>Currently I'm doing something like this:</p>
  
  <pre><code>VAR:=valueA
  step1:
      echo $(VAR)
  </code></pre>
  
  <p>Then, "make step1" will print "valueA".</p>
  
  <p>Is it possible to redefine the env var for one build step?</p>
  
  <pre><code>VAR:=valueA
  step1:
      echo $(VAR)
  step2:
      VAR:=valueB
      echo $(VAR)
  </code></pre>
  
  <p>I want "make step1" to print "valueA", but "make step1" to print "valueB".</p>