|  | @@ -125,6 +125,16 @@ PKG_PROG_PKG_CONFIG([0.20])
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				|  |  |  # Check C++ compiler supports C++0x/C++11 feature
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				|  |  |  AX_CXX_COMPILE_STDCXX_11([noext], [mandatory])
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				|  |  |  
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				|  |  | +# Check C++ compiler actually supports nullptr
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				|  |  | +AC_MSG_CHECKING([whether the c++ compiler supports nullptr])
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				|  |  | +AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
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				|  |  | +]],
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				|  |  | +[[
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				|  |  | +int *a = nullptr;
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				|  |  | +]])],
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				|  |  | +[],
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				|  |  | +[AC_MSG_FAILURE([C++ compiler does not understand nullptr, perhaps C++ compiler is too old.  Try again with new one (gcc >= 4.8.3 or clang >= 3.4)])])
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				|  |  | +
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				|  |  |  # i686-w64-mingw32-g++ 4.6 does not support override keyword. For
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				|  |  |  # those compilers, define CXX11_OVERRIDE to empty string. Otherwise
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				|  |  |  # define it as override. Use CXX11_OVERRIDE instead of override.
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