stdint.h includes definitions for format strings for printf/scanf-type functions (e.g. PRId64, ...) for all the new types. Using them is a bit clunky (e.g. printf("%"PRId64"\n",n);), but you get used to it.
What I do use (since D supports calling C printf) is have the compiler check the format string against the types of the arguments. This means it won't compile if there's a mismatch. Many C compilers do this, too.