OpenSystemsDevelopment / qpdf

When parsing content streams, allow content to be split arbitrarily
across stream boundaries.

Be explicit about the need to keep the source QPDF object around.

The code was using 1.0, but we use /FlateDecode, which didn't appear
until 1.2.

Very badly corrupted files may not have a retrievable root dictionary.
Handle that as a special case so that a more helpful error message can
be provided.

When requested, QPDFWriter will do more aggress prechecking of streams
to make sure it can actually succeed in decoding them before
attempting to do so. This will allow preservation of raw data even
when the raw data is corrupted relative to the specified filters.

QPDFObjectHandle::parseInternal now issues warnings instead of
throwing exceptions for all error conditions that it finds (except
internal logic errors) and has stronger recovery for things like
invalid tokens and malformed dictionaries. This should improve qpdf's
ability to recover from a wide range of broken files that currently
cause it to fail.

For cross compiling.

fixes #117
fixes #118
fixes #119
fixes #120

Several other infinite loop bugs were fixed by previous changes.
Include their test files in the test suite.

During parsing of an object, sometimes parts of the object have to be
resolved. An example is stream lengths. If such an object directly or
indirectly points to the object being parsed, it can cause an infinite
loop. Guard against all cases of re-entrant resolution of objects.

This is CVE-2017-9208.

The QPDF library uses object ID 0 internally as a sentinel to
represent a direct object, but prior to this fix, was not blocking
handling of 0 0 obj or 0 0 R as a special case. Creating an object in
the file with 0 0 obj could cause various infinite loops. The PDF spec
doesn't allow for object 0. Having qpdf handle object 0 might be a
better fix, but changing all the places in the code that assumes objid
== 0 means direct would be risky.

This is CVE-2017-9209.

This is CVE-2017-9210.

The description string for an error message included unparsing an
object, which is too complex of a thing to try to do while throwing an
exception. There was only one example of this in the entire codebase,
so it is not a pervasive problem. Fixing this eliminated one class of
infinite loop errors.

Don't try to install HTML or PDF documentation if we're not building
docs.

The 64 Bit file functions are supported by C++-Builder as well and
need to be used, else fseek will error out on larger files than 4 GB
like used in the large file test.

Some compilers output extra newlines in some cases.

QPDFObjectHandle was used as forward declaration, but C++-Builder 10
Seattle can't use it in std::list in such cases because the type is
undefined.

qutil.cc uses strerror to print some exceptions and adds a newline
afterwards, but strerror in Windows already adds one newline at the
end of the message and the additional one from std::endl breaks the
output vs. the expected one.

Provide notes about LibTiff and such.

Working with absolute paths makes debugging easier, but some called
scripts always need / as dir separator or won't work.

/dev/null is not portable, so use File::Spec instead, which provides
portable "paths" and especially "nul" on Windows. I changed all places
with hard coded /dev/null to be sure, while I think it only is a
problem in direct system calls, because the other executed commands go
to sh.exe from MSYS which itself should port /dev/null to NUL. The
test still pass, so shouldn't have made any harm...