title: Xcode / GCC linking issue: file is not of required architecture
body: <p>I am trying to port a windows project that includes boost 1.37 and wxwidgets to the Mac. It compiles ok, but the linker gives me a "file is not of required architecture for architecture ppc" error for libz.1.dylib and the same message as a warning a few other libraries. I also get a "duplicate dylib" warning for libz.1.dylib. </p>
  
  <p>The linker output looks like this:</p>
  
  <p>Building target “Gemsweeper Mac” of project “Gemsweeper Mac” with configuration “Debug”</p>
  
  <p>Checking Dependencies</p>
  
  <pre><code>Ld "/Users/adriangrigore/Documents/Gemsweeper Mac/Gemsweeper MacOS/Gemsweeper Mac/build/Debug/Gemsweeper Mac.app/Contents/MacOS/Gemsweeper Mac" normal i386
      cd "/Users/adriangrigore/Documents/Gemsweeper Mac/Gemsweeper MacOS/Gemsweeper Mac"
      setenv MACOSX_DEPLOYMENT_TARGET 10.4
      /Developer/usr/bin/g++-4.0 -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk "-L/Users/adriangrigore/Documents/Gemsweeper Mac/Gemsweeper MacOS/Gemsweeper Mac/build/Debug" -L/Developer/SDKs/MacOSX10.4u.sdk/usr/local/lib -L/opt/local/lib "-F/Users/adriangrigore/Documents/Gemsweeper Mac/Gemsweeper MacOS/Gemsweeper Mac/build/Debug" -F/Users/adriangrigore/Library/Frameworks -F/Developer/SDKs/MacOSX10.4u.sdk/Library/Frameworks -filelist "/Users/adriangrigore/Documents/Gemsweeper Mac/Gemsweeper MacOS/Gemsweeper Mac/build/Gemsweeper Mac.build/Debug/Gemsweeper Mac.build/Objects-normal/i386/Gemsweeper Mac.LinkFileList" -mmacosx-version-min=10.4 -L/opt/local/lib -L/Users/adriangrigore/wxwidgets-manual/wxMac-2.8.9/lib /opt/local/lib/libboost_system-mt.a /opt/local/lib/libboost_program_options-mt.a /opt/local/lib/libboost_thread-mt.a -arch ppc -arch i386 -framework IOKit -framework Carbon -framework Cocoa -framework System -framework QuickTime -framework OpenGL -framework AGL /Users/adriangrigore/wxwidgets-manual/wxMac-2.8.9/lib/libwx_mac-2.8.a -framework WebKit -lwxexpat-2.8 -lwxtiff-2.8 -lwxjpeg-2.8 -lwxpng-2.8 -lz -lpthread -liconv -framework SDL -framework Cocoa -o "/Users/adriangrigore/Documents/Gemsweeper Mac/Gemsweeper MacOS/Gemsweeper Mac/build/Debug/Gemsweeper Mac.app/Contents/MacOS/Gemsweeper Mac"
  ld warning: in /Users/adriangrigore/Documents/Gemsweeper Mac/Gemsweeper MacOS/Gemsweeper Mac/build/Gemsweeper Mac.build/Debug/Gemsweeper Mac.build/Objects-normal/i386/main.o, file is not of required architecture
  ld warning: in /Users/adriangrigore/Documents/Gemsweeper Mac/Gemsweeper MacOS/Gemsweeper Mac/build/Gemsweeper Mac.build/Debug/Gemsweeper Mac.build/Objects-normal/i386/variousfunctions-xcode.o, file is not of required architecture
  ld warning: in /Users/adriangrigore/Documents/Gemsweeper Mac/Gemsweeper MacOS/Gemsweeper Mac/build/Gemsweeper Mac.build/Debug/Gemsweeper Mac.build/Objects-normal/i386/ParticleLayers.o, file is not of required architecture
  ld warning: in /Users/adriangrigore/Documents/Gemsweeper Mac/Gemsweeper MacOS/Gemsweeper Mac/build/Gemsweeper Mac.build/Debug/Gemsweeper Mac.build/Objects-normal/i386/SDLMain.o, file is not of required architecture
  ld warning: in /opt/local/lib/libboost_system-mt.a, file is not of required architecture
  ld warning: in /opt/local/lib/libboost_program_options-mt.a, file is not of required architecture
  ld warning: in /opt/local/lib/libboost_thread-mt.a, file is not of required architecture
  ld warning: in /opt/local/lib/libz.dylib, file is not of required architecture
  ld warning: in /opt/local/lib/libiconv.dylib, file is not of required architecture
  ld: in /opt/local/lib/libz.1.dylib, file is not of required architecture for architecture ppc
  collect2: ld returned 1 exit status
  ld warning: duplicate dylib /opt/local/lib/libz.1.dylib
  ld warning: duplicate dylib /opt/local/lib/libiconv.2.dylib
  </code></pre>
  
  <p>I'm quite new to the Mac plattform, so any help would be greatly appreciated! </p>
  
  <p>Thanks,</p>
  
  <p>Adrian</p>