Xcode Linker Meldungen

ld ignoring file

ld: warning: ignoring file /Users/myname/Library/Developer/Xcode/DerivedData/<build>
/Build/Products/Debug-iphoneos/<lib> file was built for archive which is not the architecture being linked (armv6) 
Undefined symbols for architecture armv6:
 "_OBJC_CLASS_$_Class", referenced from:
     objc-class-ref in ViewController.o

Das tritt auf wenn für die entsprechende Architektur nicht gebaut wurde, dafür einfach in den Buildsettings Build Active Architecture Only auf NO setzen