title: How do I suppress '-arch', 'x86_64' flags when compiling an OpenGL/SDL application with Waf on OSX?
body: <p>I need to suppress "-arch x86_64 -arch i386" flags Waf is passing to GCC.</p>
  
  <p>I am building an <strong>SDL/Opengl</strong> application.  If I link against 32 bit SDL runtime I get error </p>
  
  <pre><code>    Undefined symbols for architecture i386:
    "_SDL_Quit", referenced from:
        __del_video in SDL_functions.c.2.o
        __init_video in SDL_functions.c.2.o
  </code></pre>
  
  <p>If I link against 64 bit SDL runtime, I get error "Undefined symbols for architecture x86_64"</p>
  
  <p>The compiler is apparently using flags </p>
  
  <pre><code>-arch x86_64 -arch i386
  </code></pre>
  
  <p>I understand that this causes GCC on OSX to try to compile for both architectures.  I want to either compile for 64 bit, or compile for 32 bit.  How do I suppress the flags for one architecture?</p>