Clean up write() return type

Add assertion about ssize_t narrowing in AIO code

Clean up read() return type

Clean up secure_read()/secure_write() return type

Make blkreftable API use size_t/ssize_t consistently

Fix for loop variables used with lengthof

Fix for loop variables

Print off_t/pgoff_t consistently as %lld

Don't cast pgoff_t to possibly 32-bit types for output

Don't cast off_t to 32-bit type for output, bug fix

Make SPI_prepare argtypes argument const

Fixes for SPI "const Datum *" use