OpenSystemsDevelopment / qpdf

This change works around STL problems with Embarcadero C++ Builder
version 10.2, but std::vector is more common than std::list in qpdf,
and this is a relatively new API, so an API change is tolerable.

Thanks to Thorsten Schöning <6223655+ams-tschoening@users.noreply.github.com>
for the fix.

This also reverts the addition of a new checkLinearization that
distinguishes errors from warnings. There's no practical distinction
between what was considered an error and what was considered a
warning.

Use PointerHolder in several places where manually memory allocation
and deallocation were being used. This helps to protect against memory
leaks when exceptions are thrown in surprising places.

This code was essentially duplicated between test_driver and
standalone_fuzz_target_runner.

In a small number of cases, it makes sense to replace an overloaded
function with a function that takes a default argument. We can do this
now because we've already broken binary compatibility since the last
release.

Have classes contain only a single private member of type
PointerHolder<Members>. This makes it safe to change the structure of
the Members class without breaking binary compatibility. Many of the
classes already follow this pattern quite successfully. This brings in
the rest of the class that are part of the public API.

This makes all integer type conversions that have potential data loss
explicit with calls that do range checks and raise an exception. After
this commit, qpdf builds with no warnings when -Wsign-conversion
-Wconversion is used with gcc or clang or when -W3 -Wd4800 is used
with MSVC. This significantly reduces the likelihood of potential
crashes from bogus integer values.

There are some parts of the code that take int when they should take
size_t or an offset. Such places would make qpdf not support files
with more than 2^31 of something that usually wouldn't be so large. In
the event that such a file shows up and is valid, at least qpdf would
raise an error in the right spot so the issue could be legitimately
addressed rather than failing in some weird way because of a silent
overflow condition.

This is the type we need for the underlying zlib implementation.

Change from unsigned long to int since we pass enumerated type values
to this field.

Fix C++ exception handling when -fvisibility=hidden

Ensure that QPDFExc and QPDFSystemError are marked visible, so that their typeinfo will not be
suppressed when -fvisibility=hidden.

Details:
    https://gcc.gnu.org/wiki/Visibility

Full parser context
    QPDF.cc(2): #include ..\..\..\..\src\include\qpdf\QPDF.hh
    QPDF.hh(48): class QPDF
    QPDF.hh(1380): decision to instantiate:  QPDF::ResolveRecorder::ResolveRecorder(QPDF *,const QPDFObjGen &)
    --- Resetting parser context for instantiation...
    QPDF.hh(799): parsing:  QPDF::ResolveRecorder::ResolveRecorder(QPDF *,const QPDFObjGen &)

Full parser context
    Pl_QPDFTokenizer.cc(1): #include ..\..\..\..\src\include\qpdf\Pl_QPDFTokenizer.hh
    Pl_QPDFTokenizer.hh(29): #include ..\..\..\..\src\include\qpdf/QPDFObjectHandle.hh
    QPDFObjectHandle.hh(51): class QPDFObjectHandle
    QPDFObjectHandle.hh(1052): decision to instantiate: PointerHolder<QPDFObject> QPDFObjectHandle::ObjAccessor::getObject(QPDFObjectHandle &)
    --- Resetting parser context for instantiation...
    QPDFObjectHandle.hh(909): parsing: PointerHolder<QPDFObject> QPDFObjectHandle::ObjAccessor::getObject(QPDFObjectHandle &)

Full parser context
    QPDF.cc(2): #include ..\..\..\..\src\include\qpdf\QPDF.hh
    QPDF.hh(47): class QPDF

Full parser context
    QPDF.cc(2): #include ..\..\..\..\src\include\qpdf\QPDF.hh
    QPDF.hh(46): class QPDF

Do not include the trailing EI, and handle cases where EI is not
preceded by a delimiter. Such cases have been seen in the wild.

We've actually seen a PDF file in the wild that contained EI
surrounded by delimiters inside the image data, which confused qpdf's
naive code. This significantly improves EI detection.

Add a version of expectInlineImage that takes an input source and
searches for EI. This is in preparation for improving the way EI is
found. This commit just refactors the code without changing the
functionality and adds tests to make sure the old and new code behave
identically.

Make explicit that copyForeignObject can be used on page objects and
will copy them properly but not update the pages tree.

When linearizing a file or getting the list of all pages in a file,
detect if the pages tree contains a duplicated page object and, if so,
shallow copy it. This makes it possible to have a one to one mapping
of page positions to page objects.

Support conversion of pages to form XObjects and placement of form
XObjects on pages.

Add getAttribute for handling inheritable page attributes, and fix
getPageImages and annotation flattening code to use it.