IOS: Library not found for -lz.1.2.3

I don't understand my error:

Ld Library/Developer/Xcode/DerivedData/Test-aywxyvnakaqhmwfbwellynwqmoik/Build/Products/Debug-iphonesimulator/Test.app/Test normal i386

cd /Users/lol/Desktop/Test

setenv MACOSX_DEPLOYMENT_TARGET 10.6

setenv PATH "/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"

/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/llvm-gcc-4.2

-arch i386 -isysroot /Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator5.0.sdk

-L/Users/lol/Library/Developer/Xcode/DerivedData/Test-aywxyvnakaqhmwfbwellynwqmoik/Build/Products/Debug-iphonesimulator

-L/Users/lol/Desktop/Test -F/Users/lol/Library/Developer/Xcode/DerivedData/Test-aywxyvnakaqhmwfbwellynwqmoik/Build/Products/Debug-iphonesimulator

-filelist /Users/lol/Library/Developer/Xcode/DerivedData/Test-aywxyvnakaqhmwfbwellynwqmoik/Build/Intermediates/Test.build/Debug-iphonesimulator/Test.build/Objects-normal/i386/Test.LinkFileList

-mmacosx-version-min=10.6 -Xlinker -objc_abi_version -Xlinker 2 -ObjC -D__IPHONE_OS_VERSION_MIN_REQUIRED=40000 -lextThree20JSON+SBJSON /Users/lol/Library/Developer/Xcode/DerivedData/Test-aywxyvnakaqhmwfbwellynwqmoik/Build/Products/Debug-iphonesimulator/libThree20UICommon.a

/Users/lol/Library/Developer/Xcode/DerivedData/Test-aywxyvnakaqhmwfbwellynwqmoik/Build/Products/Debug-iphonesimulator/libThree20.a

/Users/lol/Library/Developer/Xcode/DerivedData/Test-aywxyvnakaqhmwfbwellynwqmoik/Build/Products/Debug-iphonesimulator/libThree20UINavigator.a

/Users/lol/Library/Developer/Xcode/DerivedData/Test-aywxyvnakaqhmwfbwellynwqmoik/Build/Products/Debug-iphonesimulator/libThree20Core.a

/Users/lol/Library/Developer/Xcode/DerivedData/Test-aywxyvnakaqhmwfbwellynwqmoik/Build/Products/Debug-iphonesimulator/libThree20UI.a

/Users/lol/Library/Developer/Xcode/DerivedData/Test-aywxyvnakaqhmwfbwellynwqmoik/Build/Products/Debug-iphonesimulator/libThree20Network.a

/Users/lol/Library/Developer/Xcode/DerivedData/Test-aywxyvnakaqhmwfbwellynwqmoik/Build/Products/Debug-iphonesimulator/libThree20Style.a

-framework SystemConfiguration -framework MobileCoreServices -framework CFNetwork -framework AddressBook -framework AddressBookUI -framework QuartzCore -framework UIKit -framework Foundation -framework MessageUI -framework CoreGraphics -lz.1.2.3 -lxml2.2.7.3 -o /Users/lol/Library/Developer/Xcode/DerivedData/Test-aywxyvnakaqhmwfbwellynwqmoik/Build/Products/Debug-iphonesimulator/Test.app/Test

ld: library not found for -lz.1.2.3
Command /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/llvm-gcc-4.2 failed with exit code 1

Can you help me to understand this?

Thanks a lot ;)

The option -lz.1.2.3 means that the compiler is attempting to link the file libz.1.2.3.a, libz.1.2.3.so, or libz.1.2.3.dylib. It cannot find any of these variations and is failing because of that.

You can attempt to find the location of this file and include it in your library include path.

My question is why are you linking a specific version of z lib? Usually, it's good enough to just have -lz or -llibz.dylib. Do you have a reason for picking a specific version? What happens when you link using the un-versioned name.