[Xapian-tickets] [Xapian] #622: C++ ABI check fails with e.g. CXXFLAGS=-fabi-version=0

[Xapian]

#622: C++ ABI check fails with e.g. CXXFLAGS=-fabi-version=0
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 Reporter:  mustrumr97    |       Owner:  olly    
     Type:  defect        |      Status:  assigned
 Priority:  normal        |   Milestone:  1.3.2   
Component:  Build system  |     Version:          
 Severity:  normal        |    Keywords:          
Blockedby:                |    Platform:  All     
 Blocking:                |  
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Comment(by olly):

 This code was added in [7202] - no clues there.

 I think the concern must have been that "$CXXCPP" might not handle
 arbitrary compiler flags - for the GNU toolchain it'll be fine, but if if
 we're using a generic /lib/cpp it might not like compiler-specific flags.

 CPPFLAGS should be safe to pass to the preprocessor, but it's not helpful
 to ignore CXXFLAGS=-D_GLIBCXX_DEBUG - while it's technically incorrect
 (should be in CPPFLAGS) it works and having the build fail due to claimed
 ABI incompatibilities isn't helpful.  And passing CPPFLAGS wouldn't help
 here.

 The only alternative to passing all flags (as your patch does) seems to be
 adding -fabi-version* to the pattern to allow through - but there are
 bound to be other ABI changing flags, and even if we managed to get a
 complete list, new ones might appear with time.

 So I think let's just apply this patch, and if we do hit problems with
 some compilers or platforms, we can try to special case them.  The ABI
 checking machinery is only implemented for some compilers -  those
 defining __GNUC__ (GCC and some which pretend to be GCC), and MSVC - so
 for other compilers we could just not pass CXXFLAGS, or something.

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Ticket URL: <http://trac.xapian.org/ticket/622#comment:2>
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