Description:add unsupport api print
Team: OTHERS
Feature or Bugfix:Feature
Binary Source:No
PrivateCode(Yes/No):No

Change-Id: If54639f876c6c6d546f36f65a83e3d4ae94a58f0
Reviewed-on: http://mgit-tm.rnd.huawei.com/10522043Tested-by: Npublic jenkins <public_jenkins@notesmail.huawei.com>
Reviewed-by: Ncaoruihong 00546070 <crh.cao@huawei.com>
Reviewed-by: Nshenwei 00579521 <denny.shenwei@huawei.com>

this case statement was accidently left behind when this function
was refactored in commit e8f39ca4.

mistakenly ordering strings before addresses in the result buffer
broke the alignment that the preceding code had set up.

according to the documentation in the man pages, the GNU extension
functions gethostbyaddr_r, gethostbyname_r and gethostbyname2_r are
guaranteed to set the result pointer to NULL in case of error or no
result.

these changes reduce the size of the function somewhat and remove many
of its dependencies, including free. in principle it should now be
async-signal-safe, but this has not been verified in detail.

minor changes to error handling are also made.

they're supposed to return an error code rather than using errno.