add boost tuple include to fix build.

https://github.com/LibreCAD/LibreCAD/commit/e02f3580311d50b617427652ff77988f6bd62d9d

Index: librecad/src/lib/engine/rs_ellipse.cpp
--- librecad/src/lib/engine/rs_ellipse.cpp.orig
+++ librecad/src/lib/engine/rs_ellipse.cpp
@@ -48,6 +48,9 @@
 #include <boost/version.hpp>
 #include <boost/math/tools/roots.hpp>
 #include <boost/math/special_functions/ellint_2.hpp>
+#if BOOST_VERSION > 104500
+#include <boost/math/tools/tuple.hpp>
+#endif
 #endif
 
 namespace{
