title: Testing file existence in NMake
body: <p>In a makefile for GNU Make I use this idiom to test whether a file exists:</p>
  
  <pre><code>static:
  ifeq ($(wildcard $(FileName)),)
      # do something when the file doesn't exist
  else
      # do something different when it does
  endif
  </code></pre>
  
  <p>But it doesn't work in NMake (<code>fatal error U1000: syntax error : ')' missing in macro invocation</code>). How can I replace it? It would be perfect if the replacement works in both build systems.</p>