Reverts 2986932f31. There are more types of ints than sizes of ints, so using the stdint types doesn't work.
2986932f31
Both size_t and unsigned long long are aliases for unsigned __int64 on Win64, and causes a duplicate definition. Replacing all the integer type_name definitions with stdint.h names should avoid this problem.
This is needed for passing types to the LuaJIT ffi.