[tools] Catch exception of polymorphic type by reference

Author: tkoeppe

Diff for: tools/sections.cpp

@@ -132,7 +132,7 @@ int main(int argc, char** argv)
 
   try {
     process(argv[1]);
-  } catch (std::exception e) {
+  } catch (const std::exception& e) {
     std::cerr << e.what() << std::endl;
     return 1;
   }