title: How to use environment variables as #defines in eclipse
body: <p>I wish to assign a build number as part of my (C++) project's version information.  I'd like either g++ or Eclipse to call some external script that would bump up (or not if I choose to leave it fixed at release time) the BUILD_NUMBER and then pick up BUILD_NUMBER as a #defined value in my code.  Is this possible?  How would I do it?  Please note, I want this value to be more restricted that might be a C++ variable.  It will be a variable till we declare the build to be, say, beta.  Then it'll lock down.</p>
  
  <p>As an alternative, I could use the SVN version number.  It is available to Eclipse to stuff into an environment var or #define-d value?</p>
  
  <p>I have looked around google and in the Eclipse fora and find lots of entries that share the same search words as I would use to ask this question.  Nothing quite on-topic turned up.</p>