...because our IntelliSense parser doesn't have support for blocks, but we get back __BLOCKS__=1 when querying clang compilers on Mac. This could potentially break IntelliSense with any code that checks __BLOCKS__ and uses ^ blocks syntax (http://clang.llvm.org/docs/BlockLanguageSpec.html).

The fix (and workaround) is to pass -fno-blocks when querying clang compilers (with Mac clang -fblocks is the default)...the main difficulty to is to avoid using -fno-blocks with gcc, which doesn't support that flag.