* It's assumed all systems this software will build on are
  equipped with a reasonably recent tar program.

* This way, tests and examples can also rely on macro definitions
  like HAVE_VOLATILE.

* This fixes an issue when builds are performed
  1. with PGI compilers
  2. on x86_64 platforms that support __lzcnt64
  3. using configure option --with-idxtype=long and
  4. the compiler has no support for __builtin_clzl
  and which causes stride overlap computations to fail.