OpenSystemsDevelopment / qpdf

Specifically, if a stream had its stream data replaced and had
indirect /Filter or /DecodeParms, it would result in non-silent loss
of data and/or internal error.

Fixes a crash found by fuzzing.

StreamDataProvider::provideStreamData now has a rich enough API for it
to effectively proxy to pipeStreamData.

Fixes qpdf/qpdf#419

It seems better not to compress signature dictionaries. Various PDF
digital signing tools, including Adobe Acrobat Reader DC, do not
compress signature dictionaries.

Table 8.93 "Entries in a signature dictionary" in PDF 1.5 reference
describes that /ByteRange in the signature dictionary shall be used to
describe a digest that does not include the signature value
(/Contents) itself.

The byte ranges cannot be determined if the dictionary is compressed.

When seeing to a position based on a value read from the input, we are
prone to integer overflow (fuzz issue 15442). Seek in two stages to
move the overflow check into the input source code.

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.

There are more to handle, but this resolves an issue already caught by
oss-fuzz.

* [bcc32 Error] QPDF.cc(375): E2268 Call to undefined function 'atof'
  Full parser context
    QPDF.cc(358): parsing: void QPDF::parse(const char *)

* [bcc32 Error] QPDFTokenizer.cc(183): E2268 Call to undefined function 'strtol'
  Full parser context
    QPDFTokenizer.cc(163): parsing: void QPDFTokenizer::resolveLiteral()

* [bcc32 Error] pdf-split-pages.cc(52): E2268 Call to undefined function 'exit'
  Full parser context
    pdf-split-pages.cc(50): parsing: void usage()

* PR #295: Including "cstdlib" should be replaced with "stdlib.h" to be more consistent. At the same time I changed the order of the surrounding includes to reflect alphabetical order, because at some files this already have been the case.

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