Don't use %zu

Eventually we'll need to make sure that a) libroken's stdint.h defines
the max integer types, b) the libroken *printf()s can handle all the
standard length and conversion specifiers.
Don't need, so don't use, stdbool.h
libedit should check HAVE_STDINT_H (S8)
Make lib/otp/Makefile.am use -I$(DBHEADER)