Better match for HDF5's legacy FindSZIP.cmake

Signed-off-by: Miloš Komarčević <miloskomarcevic@aim.com>

* CMake: (fix) Changed names of the resulting config files.

Changed the name LibaecTargets.cmake, LibaecConfig.cmake and
LibaecConfigVersion.cmake to libaecTargets.cmake, libaecConfig.cmake
and libaecConfigVersion.cmake such that these files can be found
by cmake on a Linux machine.

* CMake: (feature) Better integration with HDF5.

- Changed the build such that always a static and shared library
  with be built.
- Rewritten CMake config files such that
  - One can select the shared or static library.
  - Set several libaec variables such one can, for example,
    check if the libaec library is found.
  - Set several Szip variables for the same reason as for
    setting the libaec variables. This is useful for a better
    integration with HDF5 when building HDF5 from scratch.

Signed-off-by: Brennan Ashton <bashton@brennanashton.com>

- Localize vars
- Add const
- Simplify status reporting and status var
- Free any malloced memory in the OOM case
- Remove unnecessary goto
- Use stderr for error message

Thanks to Kurt Schwehr for finding this

Found by UBSan

C99 is now required.  Therefore HAVE_STDINT_H is no longer necessary.

encode_accessors.h: include "config.h" to allow header to stand alone

Minor cleanup of fuzz_target.cc

codespell: dependance  ==> dependence

Some compilers do header precompilation and this requires that each
header can stand alone.  Including config.h sets HAVE_STDINT_H.

- Include What You Use (IWYU) - add cstddef
- Convert to C++ includes of C headers
- Localize vars
- Combine definition and initialization of dest
- Convert C cast to C++ cast
- Remove unused source var