[boost] [test] [Patch] Unconditional use of non-standard functions.

Boost.Test has just started using ::fedisableexcept and ::feenableexcept unconditionally - even though these are GLIBC specific extensions - which presumably is why Boost.Test is currently failing so many tests :-( I've just committed a patch to restrict the use of these functions to GLIBC platforms that have the GNU extensions enabled: see https://svn.boost.org/trac/boost/changeset/62194/trunk/boost/test/impl/execu.... Please feel free to change the logic for any other platforms that may have these functions.... but for now, hopefully we can get back to testing Boost again! Cheers, John.