Fix compilation with 2.6.x series.

rtl/inc/objpas.inc:
  * IsRefCounted: return False for 2.6.x series
  * RefCountOffset: return 0 for 2.6.x series


git-svn-id: http://svn.freepascal.org/svn/fpc/branches/svenbarth@28907 3ad0048d-3df7-0310-abae-a5850022a9f2
Rename ARC related methods of TObject so that they conflict less with existing methods/fields (in this case the "refcount" field of TSymtable in the compiler)

rtl/inc/objpash.inc & objpas.inc:
  * prefix methods IncRef, DecRef, RefCount, IsRefCount and RefCountOffset with 'ARC'


git-svn-id: http://svn.freepascal.org/svn/fpc/branches/svenbarth@28908 3ad0048d-3df7-0310-abae-a5850022a9f2