BIND 10 #1158: suggestion: avoid OS-specific switch in configure.ac

[BIND 10 Development]

#1158: suggestion: avoid OS-specific switch in configure.ac
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            Reporter:  jinmei        |                        Owner:
                Type:  defect        |  UnAssigned
            Priority:  major         |                       Status:  new
           Component:  build system  |                    Milestone:  Next-
           Sensitive:  0             |  Sprint-Proposed
         Sub-Project:  Core          |                     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 that in #1155 the following change was introduced to
 configure.ac:
 {{{
 *-solaris*)
 [...]
         # In Solaris, IN6ADDR_ANY_INIT and IN6ADDR_LOOPBACK_INIT need
 -Wno-missing-braces
         B10_CXXFLAGS="$B10_CXXFLAGS -Wno-missing-braces"
         ;;
 }}}

 I have a few concerns with this approach:

 - In general, such OS specific switch is discouraged in autoconf.
   And, in fact, not all Solaris versions/installments have this
   problem as some of our buildbot showed.  For such "cleaner" Solaris,
   this setting weakens compiler warning unnecessarily.  A better test
   is to use AC_TRY_COMPILE with using the offending IN6ADDR_ macros
   and specify -Wno-xxx only when it's necessary.

 - If I understand it correctly, this problem happens only where ASIO
   headers are directly included (mainly in libasiolink and libasiodns,
   with (inappropriate) a couple of possible exceptions).  We should
   limit the place of weakening the warning to where it's absolutely
   necessary.

-- 
Ticket URL: <http://bind10.isc.org/ticket/1158>
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