To build from source for Linux or other UNIX/UNIX-like systems, it is
generally sufficient to download just the source qpdf-<version>.tar.gz
file.

For Windows, there are several additional files that you might want to
download.

 * qpdf-<version>-bin-mingw32.zip

   If you just want to use the qpdf command line program or use the
   qpdf DLL's C-language interface, you can download this file.  You
   can also download this version if you are using MINGW's gcc 4.6 (or
   a binary compatible version) and want to program using the C++
   interface.

 * qpdf-<version>-bin-mingw64.zip

   A 64-bit version built with mingw.  Use this for 64-bit Windows
   systems.  The 32-bit version will also work on Windows 64-bit.
   Both the 32-bit and the 64-bit version support files over 2 GB in
   size, but you may find it easier to integrate this with your own
   software if you use the 64-bit version.

 * qpdf-<version>-bin-msvc32.zip

   If you want to program using qpdf's C++ interface and you are using
   Microsoft Visual C++ 2010 in 32-bit mode, you can download this
   file.

 * qpdf-<version>-bin-msvc64.zip

   If you want to program using qpdf's C++ interface and you are using
   Microsoft Visual C++ 2010 in 64-bit mode, you can download this
   file.

 * qpdf-external-libs-bin.zip

   If you want to build qpdf for Windows yourself with either MINGW or
   MSVC 2010, you can download this file and extract it inside the
   qpdf source distribution.  Please refer to README-windows.txt in
   the qpdf source distribution for additional details.  Note that you
   need the 2012-06-20 version or later to be able to build qpdf 3.0
   or newer.  The 2009-10-24 version is required for qpdf 2.3.1 or
   older.

 * qpdf-external-libs-src.zip

   If you want to build the external libraries on your own (for
   Windows or anything else), you can download this archive.  In
   addition to including unmodified distributions of pcre and zlib, it
   includes a README file and some scripts to help you build them for
   Windows.