title: How to pass a QMAKE variable from the command line?
body: <p>I am to trying cross-compile pile Qt from a Linux terminal.  When I run qmake it applies the mkspecs qmake.conf in my context in such manner that the CROSS_COMPILE variable must be defined.  For example, there is a critical conf line that looks like this:</p>
  
  <pre><code>QMAKE_CXX               = $${CROSS_COMPILE}g++
  </code></pre>
  
  <p>Qmake returns an error though which clearly indicates $${CROSS_COMPILE} is not being resolved.  It is simply using "g++" instead of the whole value which ought to be there.  </p>
  
  <p>I've tried to invoke qmake and define the variable from a bash script like this:</p>
  
  <pre><code>qmake qt.pro "CROSS_COMPILE=${CROSS_COMPILE}"
  </code></pre>
  
  <p>And like this :</p>
  
  <pre><code>qmake qt.pro -- "CROSS_COMPILE=${CROSS_COMPILE}"
  </code></pre>
  
  <p>And a few other such stabs at it.  I've also tried hard coding the value in that command in case that had anything to do with it.  I've tried defining this as an environmental variable too (just in case)...</p>
  
  <p>Nothing works.  Yet, I've seen piles of examples where this syntax seems to be valid.  What am doing wrong?  Could there be a character escape complication?</p>