Add a note why OSX 10.8 SDK is used instead of 10.9 SDK
Silence a compiler warning, with something that looks like the possibly intended behavior
but is the opposite of the compiler order of evaluation.

/Users/martin/OpenSC/OpenSC.tokend/build/security_cdsa_utilities.framework/Headers/cssmpods.h:59:22: warning: operator '<<' has lower precedence than '+'; '+' will be evaluated first [-Wshift-op-parentheses]