xmppframework: "Undefined symbols for architecture x86_64"

Question

I am developing a live chat software for iOS using xmppframework. My xCode version is 6.4(6e35b). I did import the xmpp folder exactly follow the Readme document. However, it gives me error like undefined symbols for x86_64 when I tried to use this xmppframework:

My settings:

"other linker flag" = "-lxml2 -lresolv"
"header search path" = "$(inherited) /usr/include/libxml2 
"link binary withibraries" = libresolv.dylib
                           libxml2.dylib
                           coreGraphics.framework 
                           Foundation.framework
                           UIKit.framework
                           CFNetwork.framework
                           CoreData.framework
                           SystemConfiguration.framework
                           CoreLocation.framework
                           Security.framework
                           libidn.a

$(PROJECT_DIR)/xmpp(recursive) $(SRCROOT)"

My architecture settings:

I think the problem probably is I didn't have x86_64 architecture in my computer. If so, how can I add that into my computer?

I googled this problem and found some answers lipo -info libCompuwareUEM.a to check if there is x86_64 and get result can't open input file: libCompuwareUEM.a (No such file or directory), it's that means I don't have that architecture file?