This explicitly uses C linkage for the library code used by the test to work
around some compilers (Solaris Studio 12.4) that implicitly assume incorrect
linkage information. Since something else entirely is being tested here,
this allows the test to proceed as needed on the affected platforms.
Instead of relying on that some development package is installed on the
system, now a tiny library is built, which is the searched and used
during the test.
Alex