OpenSystemsDevelopment / qpdf

* Make it a runtime error, not a logic error
* Include additional information
* Capture it properly in checkLinearization

Create a computationally and memory efficient implementation of name
and number trees that does binary searches as intended by the data
structure rather than loading into a map, which can use a great deal
of memory and can be very slow.

Turns out unreadCh is much more efficient than seek(-1, SEEK_CUR).
Update comments and code to reflect this.

We need to run qpdf --show-crypto.

This is all that ever worked. The test suite was trying to do
something different from ClosedFileInputSource.

When possible, use `for (auto&` or `for (auto const&` when iterating
using C++-11 style iterators.

Build fails on gcc 4.8 since version 9.1.1 and commit
752416554086d5d34323bc14164d5084db83cfbd:

libtests/cxx11.cc: In function 'void do_regex()':
libtests/cxx11.cc:347:42: error: 'strlen' is not a member of 'std'
     std::cregex_iterator m3(str7, str7 + std::strlen(str7), expr4);
                                          ^

To fix the build failure, add missing include on cstring

Fixes:
 - http://autobuild.buildroot.org/results/ad7fb68ae87850a85509eed80fd0cae8721b10c5

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>

This commit adds the preserve_eol flags but doesn't implement EOL
preservation yet.

If QPDF_CRYPTO_PROVIDER is set, just run the tests for the given
provider. This is to support cases of running the entire test suite
for each provider. If QPDF_CRYPTO_PROVIDER is not set, run the tests
that exercise the cyrpto provider for each available provider.

This code was essentially duplicated between test_driver and
standalone_fuzz_target_runner.

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.