Fix a couple of clang compiler warnings:

-Wunused-variable
-Winconsistent-missing-override
-Wdelete-non-virtual-dtor
-Wunused-private-field
-Wformat

src/Mod/Path/libarea/PythonStuff.cpp

@@ -75,8 +75,10 @@ static void print_curve(const CCurve& c)
 	std::size_t nvertices = c.m_vertices.size();
 #if defined SIZEOF_SIZE_T && SIZEOF_SIZE_T == 4
 	printf("number of vertices = %d\n", nvertices);
-#else
+#elif defined(_WIN32)
 	printf("number of vertices = %Iu\n", nvertices);
+#else
+	printf("number of vertices = %lu\n", nvertices);
 #endif
 	int i = 0;
 	for(std::list<CVertex>::const_iterator It = c.m_vertices.begin(); It != c.m_vertices.end(); It++, i++)