Try to be a bit more paranoid about C++11 support

Author: mitchblank

timsort.hpp

@@ -62,18 +62,19 @@
 #    if defined(__cplusplus) && __cplusplus < 201103L
 #      undef GFX_TIMSORT_USE_CXX11
 #    endif
-#    ifdef _LIBCPP_VERSION
-#      if defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) || defined(_LIBCPP_CXX03_LANG)
+#    ifdef __GLIBCXX__
+#      if __GLIBCXX__ < 20150422
 #        undef GFX_TIMSORT_USE_CXX11
 #      endif
-#    elif defined(__GLIBCXX__)
-#      if __GLIBCXX__ < 20150422
+#    endif
+#    ifdef _LIBCPP_VERSION
+#      if defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) || defined(_LIBCPP_CXX03_LANG)
 #        undef GFX_TIMSORT_USE_CXX11
 #      endif
 #    endif
 #    ifdef __clang__
 #      ifdef __has_feature
-#        if !(__has_feature(cxx_rvalue_references))
+#        if !(__has_feature(cxx_rvalue_references) && __has_feature(is_trivially_copyable))
 #          undef GFX_TIMSORT_USE_CXX11
 #        endif
 #      else