[packages,*] Added SDKVersion to C.ICCompilerOptionsOSX interface, supported on both Clang and llvm-gcc compilers. llvm-gcc compiler also supports framework search paths
[packages,*] Adding C.ICCompilerOptionsOSX.DeploymentTarget, to set the minimum version of OSX to run on
[packages,*] Adding C.ICCompilerOptionsOSX.SupportedPlatform with C.EOSXPlatform enum. Defaults to macosx.
[packages,*] Added C.ICCompilerOptionsOSX.CompilerName, taking the name of the compiler in reverse DNS notation. This isn't usually required to be set as the default suffices, especially with Xcode5+ that only has Clang as the compiler