On hppa, the function pointers used in vtables point to function descriptors.  In order for  CMP_VPTR
to work, we need to extract the actual function address from the function descriptor.  On linux, we further
need to canonicalize the function pointer due to the lazy binding of function descriptors.

Tested on hppa-unknown-linux-gnu, hhpa2.0w-hp-hpux11.11 and hppa64-hp-hpux11.11.  Committed
to trunk and gcc-6 branch.

Dave
--
John David Anglin	dave.anglin@bell.net