You'd define architecture-specific typedefs to deal with these cases in a portable way. The C standard already has types like int_fast8_t that are similar in principle.
See, why would you need an "architecture specific typedef" in order to represent the day of the month, or the number of arguments in main "in a portable way".
int does it in a portable way already.
int is architecture specific too, and it's been "muddled" plenty due to backward compatibility concerns. Using typedefs throughout would be a cleaner choice if we were starting from scratch.
It's just muddled thinking.