Reduce warning
Update to recommended configurations for 10.9
Fix linking libcommonCrypto error by replacing it with libSystem

Error:

    ld: warning: directory not found for option '-L"/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib/system"'
    ld: cannot link directly with /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib/system/libcommonCrypto.dylib.  Link against the umbrella framework 'System.framework' instead. for architecture x86_64
    clang: error: linker command failed with exit code 1 (use -v to see invocation)