BIND 10 #2340: build failures with newer versions of clang++

[BIND 10 Development]

#2340: build failures with newer versions of clang++
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            Reporter:  jinmei        |                        Owner:
                Type:  defect        |  UnAssigned
            Priority:  medium        |                       Status:  new
           Component:  build system  |                    Milestone:  Next-
           Sensitive:  0             |  Sprint-Proposed
         Sub-Project:  DNS           |                     Keywords:
Estimated Difficulty:  0             |              Defect Severity:  N/A
         Total Hours:  0             |  Feature Depending on Ticket:
                                     |          Add Hours to Ticket:  0
                                     |                    Internal?:  0
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 I noticed this while I tried to build BIND 10 on Mac OS X 10.8.
 As a result of upgrading the OS I ended up upgrading Xcode, which
 installed a bleeding edge version of clang.

 It caused a few new build failures:

 - clang is now more strict about "unused variables" (some of which I
   suspect are mostly false positives).
 - it's more sensitive to the "driver" (such as compiler or linker)
   argument (options), and treats some of them as a fatal error with
   -Werror.  Specifically, the -pthread option specified some part of
   the BIND 10 code caused fatal build errors.  It also made it
   possible to use clang++ via ccache.

 Fixing or working around the first issue was easy.  For the second
 issue, I propose disabling the warning by specifying
 -Qunused-arguments.  While it may be possible to carefully set and
 position compiler options to avoid the issue, I'm afraid it can soon
 repeat as we support multiple compilers.  Suppressing warnings is
 generally bad, but in this case it's at least irrelevant to ensuring
 the code quality.

 I have a private branch implementing the proposal.  I'm going to push
 it and move this ticket to the review queue.

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Ticket URL: <http://bind10.isc.org/ticket/2340>
BIND 10 Development <http://bind10.isc.org>
BIND 10 Development