xcode 4.5.1; mountain lion; "problem" with GKPeerPickerController

ANYONE ELSE HIT THIS PROBLEM? SOLUTION?

Ld /Users/RoamingRooster/Library/Developer/Xcode/DerivedData/TicTac-hdcnutahlljppharevpdzmlllyky/Build/Products/Debug-iphonesimulator/TicTac.app/TicTac normal i386
cd /Users/RoamingRooster/Documents/PROJECTS
setenv IPHONEOS_DEPLOYMENT_TARGET 5.0
setenv PATH "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch i386 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.0.sdk -L/Users/RoamingRooster/Library/Developer/Xcode/DerivedData/TicTac-hdcnutahlljppharevpdzmlllyky/Build/Products/Debug-iphonesimulator -F/Users/RoamingRooster/Library/Developer/Xcode/DerivedData/TicTac-hdcnutahlljppharevpdzmlllyky/Build/Products/Debug-iphonesimulator -filelist /Users/RoamingRooster/Library/Developer/Xcode/DerivedData/TicTac-hdcnutahlljppharevpdzmlllyky/Build/Intermediates/TicTac.build/Debug-iphonesimulator/TicTac.build/Objects-normal/i386/TicTac.LinkFileList -Xlinker -objc_abi_version -Xlinker 2 -fobjc-arc -fobjc-link-runtime -Xlinker -no_implicit_dylibs -mios-simulator-version-min=5.0 -framework Foundation -framework UIKit -o /Users/RoamingRooster/Library/Developer/Xcode/DerivedData/TicTac-hdcnutahlljppharevpdzmlllyky/Build/Products/Debug-iphonesimulator/TicTac.app/TicTac

Undefined symbols for architecture i386:
"_OBJC_CLASS_$_GKPeerPickerController", referenced from:
objc-class-ref in ViewController.o
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)

(null): "_OBJC_CLASS_$_GKPeerPickerController", referenced from:
(null): Objc-class-ref in ViewController.o
(null): Symbol(s) not found for architecture i386

(null): Linker command failed with exit code 1 (use -v to see invocation)

resolution: add Game Kit to Build Phases -> Link Binary With Libraries