Stop "developer tools access needs to take control of another process for debugging to continue" alert

There's a much simpler solution for this. Try running the following command:

sudo /usr/sbin/DevToolsSecurity --enable

enable develoer mode: In Terminal run this: DevToolsSecurity -enable

Per Zev Eisenberg's answer, reinstalling Xcode 4.2.1 worked. However, it might be easier to just patch the /etc/authorization file with the following diff.

        <key>system.privilege.taskport.debug</key> 
        <dict>
            <key>allow-root</key>
            <false/>
            <key>class</key>
-           <string>user</string>
+           <string>rule</string>
            <key>comment</key>
            <string>For use by Apple.  WARNING: administrators are advised
             not to modify this right.</string>
            <key>default-button</key>
            <dict>
            ...
            </dict>
            <key>default-prompt</key>
            <dict>
            ...
            </dict>
-           <key>group</key>
-           <string>_developer</string>
            <key>shared</key>
            <true/>
-           <key>timeout</key>
-           <integer>36000</integer>
+           <key>k-of-n</key>
+           <integer>1</integer>
+           <key>rule</key>
+           <array>
+               <string>is-admin</string>
+               <string>is-developer</string>
+               <string>authenticate-developer</string>
+           </array>
        </dict>