Xcode debugger: cmd line application - start with sudo?

Running XCode as root is a bad idea.

There is an option for this in XCode (6.2):

• Product -> Scheme -> Edit Scheme
• Select the "Run" configuration
• Change the radio button for "Debug Process As" to "root"

Have you tried starting Xcode with sudo?
The processes it spawns (gdb,...) should also run with superuser privileges:

sudo /Applications/Xcode.app/Contents/MacOS/Xcode