not some other tool (file system checker on Tru64).

Patch originally supplied by Peter O'Gorman, slightly modified by me.

Bug#27739 "build fails on Tru64 due to icheck test in configure"


configure.in:
  We use "icheck" as a tool to check against ABI changes.
  However, some systems (like Tru64) have "icheck" as a file system checker.
  So if "icheck" is found, it should be verified that this really is the
  ABI checker and not some other tool.
  
  Patch originally supplied by Peter O'Gorman, slightly modified by me.
  
  Bug#27739 "build fails on Tru64 due to icheck test in configure"