iOS: How to fix the following warning issues?

Question

Ever since updating to xcode 7. I received a lot of warnings that I am not familiar with and have no idea what they are.

warning: /Users/minidragon/Library/Developer/Xcode/DerivedData/ModuleCache/HJUIXHI06SFW/CoreGraphics-1YQ59ILDR3NYI.pcm: No such file or directory
while processing /Users/tipsy/Library/Developer/Xcode/DerivedData/rainbowtail-ceybamfcswlsqubjdieleicoaimx/Build/Products/Release-iphoneos/libcocos2d.a(cpRatchetJoint.o):
warning: /Users/tipsy/Library/Developer/Xcode/DerivedData/ModuleCache/HJUIXHI06SFW/CoreGraphics-1YQ59ILDR3NYI.pcm: No object file for requested architecture
while processing /Users/tipsy/Library/Developer/Xcode/DerivedData/rainbowtail-ceybamfcswlsqubjdieleicoaimx/Build/Products/Release-iphoneos/libcocos2d.a(cpRatchetJoint.o):
warning: Could not resolve external type c:@S@CGPoint

Does anyone know what they are and how to fix them? Thanks in advance.