Code signing is required for product type 'WatchKit App' in SDK

The error above appeared after updating to Xcode 8.  Everything built fine before, but now it built with the error:

WatchKit App requires a provisioning profile. Select a provisioning profile for the "Debug" build configuration in the project editor
Code signing is required for product type 'WatchKit App' in SDK 'iOS 10.0'

The solution is to make sure "Automatically managed signing" is checked for each target in the General tab.  If it is already checked, uncheck it and re-check it.

Undefined symbols for architecture armv7

This was a error I was getting after trying to install Xcode 3.2.6 when I already had Xcode 4.x.  I think installing Xcode 3.2.6 screwed up the codesigning.  This article from stack overflow saved me from throwing my mac out the window.

http://stackoverflow.com/questions/4842717/iphone-codesign-object-file-format-invalid-or-unsuitable

It basically makes a symlink to the latest code sign.

sudo mv /usr/bin/codesign_allocate /usr/bin/codesign_allocate_old sudo ln -s /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/codesign_allocate /usr/bin