* CopSTASH_set(..., NULL) does not work with older threaded perls
  (5.16.x and older)

  Workaround by using the old code before commit
  8eb3ec51a58dd02334118d8f0aa1bebb5704d15c code in this case. Detect
  problem with a new C test file copstashset.c.
* SvNV_nomg is not available with older perls (5.13.1 and older) ---
  in these cases, use again SvNV
* inc'd VERSION to 804.030_501
* updated Changes for Tk-804.030_501