hppa: fix dladdr [BZ #19415]

hppa: fix dladdr [BZ #19415]

The attached patch fixes dladdr on hppa.

Instead of using the generic version of _dl_lookup_address, we use an
implementation more or less modeled after __canonicalize_funcptr_for_compare()
in gcc.  The function pointer is analyzed and if it points to the
trampoline used to call _dl_runtime_resolve just before the global
offset table, then we call _dl_fixup to resolve the function pointer.
Then, we return the instruction pointer from the first word of the
descriptor.

The change fixes the testcase provided in [BZ #19415] and the Debian
nss package now builds successfully.