OpenSystemsDevelopment / qpdf

Rather than checking consistency of libqpdf.map, generate it.

If not available, give an error.  The user may also configure qpdf to
use an insecure random number generator.

Make them safer by avoiding any internal limits and replacing sprintf
with std::ostringstream.

Enable C4996, deprecation/security warnings, which helps for Windows 8
certification.  Stop enabling C4267, which was warning about
conversions between size_t and other integer types.

Also separate C and C++ warning flags.

Make --enable-werror work properly on msvc, handle extra warnings
flags for msvc in configure.ac instead of hardcoding into
make/msvc.mk, separate warnings flags into WFLAGS in autoconf.mk to
avoid duplication and to make it easier to override.

3.0.rc1

LARGE_FILE_TEST_PATH -> QPDF_LARGE_FILE_TEST_PATH
SKIP_TEST_COMPARE_IMAGES -> QPDF_SKIP_TEST_COMPARE_IMAGES

Incorrectly stated that default is disabled when it is actually
enabled.

Provide option to show test output if requested.

off_t is used internally only when needed to talk to standard
libraries.  This requires that the "long long" type be supported by
the compiler.

Update the build to support new external-libs layout, and autoconf
options to specify windows word size.  Split make_windows_releases
into multiple scripts.

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.

For ELF systems, turn on versioned symbols by default, and add a
configure option to enable or disable them.