title: kextutil: no compatible dependency found for com.apple.iokit.IOUSBFamily
body: <p>Kextutil failed when loading my driver on Mac-pro 10.6.8, but it's OK on iMac 10.6.8. 
  You're appreciated if you tell me something about that! Thanks</p>
  
  <p>Information:</p>
  
  <pre><code>YAN:W$ uname -a
  Darwin YAN.local 10.8.0 Darwin Kernel Version 10.8.0: Tue Jun  7 16:32:41 PDT 2011; root:xnu-1504.15.3~1/RELEASE_X86_64 x86_64
  YAN:W$ sudo kextutil /System/Library/Extensions/MyDriver64.kext
  /tmp/MyDriver64.kext - no compatible dependency found for com.apple.iokit.IOUSBFamily.
  /tmp/MyDriver64.kext - no compatible dependency found for com.apple.kpi.iokit.
  /tmp/MyDriver64.kext - no compatible dependency found for com.apple.kpi.libkern.
  /tmp/MyDriver64.kext - no compatible dependency found for com.apple.kpi.mach.
  /tmp/MyDriver64.kext - no compatible dependency found for com.apple.iokit.IOUSBFamily.
  /tmp/MyDriver64.kext - no compatible dependency found for com.apple.kpi.iokit.
  /tmp/MyDriver64.kext - no compatible dependency found for com.apple.kpi.libkern.
  /tmp/MyDriver64.kext - no compatible dependency found for com.apple.kpi.mach.
  /tmp/MyDriver64.kext - no compatible dependency found for com.apple.iokit.IOUSBFamily.
  /tmp/MyDriver64.kext - no compatible dependency found for com.apple.kpi.iokit.
  /tmp/MyDriver64.kext - no compatible dependency found for com.apple.kpi.libkern.
  /tmp/MyDriver64.kext - no compatible dependency found for com.apple.kpi.mach.
  /tmp/MyDriver64.kext has problems:
  Dependency Resolution Failures: 
  Only incompatible kexts found for these libraries: 
      com.apple.iokit.IOUSBFamily
      com.apple.kpi.iokit
      com.apple.kpi.libkern
      com.apple.kpi.mach
  </code></pre>