"clang failed with exit code 254" when building for arm64 with iOS7.1 beta4

[vzqwer]

BlocksKit installed with cocoapods according to https://github.com/pandamonia/BlocksKit/issues/178#issuecomment-31584013

pod 'BlocksKit', :git => 'https://github.com/pandamonia/BlocksKit.git', :branch => 'next'

When building get

CompileC .../Pods.build/Debug-iphoneos/Pods-BlocksKit.build/Objects-normal/arm64/sysv-8C85F8020C6BDA6B.o BlocksKit/ffi-mini/src/aarch64/sysv.S normal arm64 assembler-with-cpp com.apple.compilers.llvm.clang.1_0.compiler

failed with error message

Command /Applications/Xcode51-Beta4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang failed with exit code 254

[zwaldowski]

Known issue that's been reported to Apple: http://openradar.appspot.com/radar?id=4602415550562304

[zwaldowski]

Resolved in Xcode 5.1 Beta 5/5B103i (Clang-503.0.19/LLVM 3.4svn).