Fix printf errors.

The compiler will help find mismatches between printf formats and
arguments if you let it.  This patch adds the necessary attributes to
declarations in include/common.h, then begins to correct the resulting
compiler warnings.  Some of these were bugs, e.g., "$d" instead of
"%d" and incorrect arguments.  Others were just annoying, like
int-long mismatches on a system where both are 32 bits.  It's worth
fixing the annoying errors to catch the real ones.

Signed-off-by: Andrew Klossner <andrew@cesa.opbu.xerox.com>