"All the major C compilers have committed to implementing these features": including MSVC, which doesn't even implement C99?

"Static compile-time assertions allow the use of sizeof() and friends" could already be done with the preprocessor and typedefs; see e.g. C_ASSERT: http://msdn.microsoft.com/en-us/library/windows/desktop/ms67... It will still be nice to have a standard way to do it, though.