[PATCH] spirit: fix changesign wrapper

With powerpc target and uClibc toolchain the spirit library doesn't
build properly due to an invalid field access.

"bits" field is intended only for internal use in
include/boost/math/special_functions/sign.hpp not from
include/boost/spirit/home/support/detail/sign.hpp.

This lead to the following build failure:

In file included from ./boost/spirit/home/qi/numeric/detail/real_impl.hpp:22:0,
                 from ./boost/spirit/home/qi/numeric/real.hpp:21,
                 from ./boost/spirit/home/qi/numeric.hpp:17,
                 from ./boost/spirit/include/qi_core.hpp:23,
                 from libs/log/src/default_filter_factory.cpp:21:
./boost/spirit/home/support/detail/sign.hpp: In instantiation of 'T boost::spirit::detail::changesign(T) [with T = long double]':
./boost/spirit/home/qi/numeric/detail/real_impl.hpp:94:50:   required from here
./boost/spirit/home/support/detail/sign.hpp:60:36: error:
no type named 'bits' in 'traits_type {aka struct boost::math::detail::fp_traits_non_native<long double, boost::math::detail::extended_double_precision>}'
         typename traits_type::bits a;

Simply call (boost::math::changesign)(x) from
include/boost/spirit/home/support/detail/sign.hpp to fixes this.

Fixes:
http://autobuild.buildroot.net/results/be1/be1069e8528d299f487f431f7e2d793413ccbab8/build-end.log

Signed-off-by: Romain Naour <[email protected]>
---
 include/boost/spirit/home/support/detail/sign.hpp | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/include/boost/spirit/home/support/detail/sign.hpp b/include/boost/spirit/home/support/detail/sign.hpp
index 7c1bfb0..2a64e6a 100644
--- a/include/boost/spirit/home/support/detail/sign.hpp
+++ b/include/boost/spirit/home/support/detail/sign.hpp
@@ -55,13 +55,7 @@ namespace boost { namespace spirit { namespace detail
 #if defined(BOOST_MATH_USE_STD_FPCLASSIFY) && !defined(BOOST_MATH_DISABLE_STD_FPCLASSIFY)
         return -x;
 #else
-        typedef typename math::detail::fp_traits<T>::type traits_type;
-
-        typename traits_type::bits a;
-        traits_type::get_bits(x, a);
-        a ^= traits_type::sign;
-        traits_type::set_bits(x, a);
-        return x;
+        return (boost::math::changesign)(x);
 #endif
     }
 #endif
-- 
1.9.3


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