Prior to the cmake conversion, several private classes had methods
that were exported into the shared library so they could be tested
with libtests. With cmake, we build libtests using an object library,
so this is no longer necessary. The methods that are disappearing from
the ABI were never exposed through public headers, so no code should
be using them. Removal had to wait until the window for ABI-breaking
changes was open.
For non-encrypted files, determinstic ID generation uses file contents
instead of timestamp and file name. At a small runtime cost, this
enables generation of the same /ID if the same inputs are converted in
the same way multiple times.
Significantly improve the code's use of off_t for file offsets, size_t
for memory sizes, and integer types in cases where there has to be
compatibility with external interfaces. Rework sections of the code
that would have prevented qpdf from working on files larger than 2 (or
maybe 4) GB in size.
