Issue 4550: Avoid "using namespace std;" in included files (Take 2)

lily/paper-column.cc

 /*
   This file is part of LilyPond, the GNU music typesetter.
 
   Copyright (C) 1997--2020 Han-Wen Nienhuys <hanwen@xs4all.nl>
 
   LilyPond is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 
@@ skipping 21 matching lines @@
 #include "rhythmic-head.hh"
 #include "separation-item.hh"
 #include "skyline-pair.hh"
 #include "spaceable-grob.hh"
 #include "spring.hh"
 #include "string-convert.hh"
 #include "system.hh"
 #include "text-interface.hh"
 #include "warn.hh"
 
+using std::string;
+using std::vector;
+
 bool
 Paper_column::internal_set_as_bound_of_spanner (Spanner *s, Direction)
 {
   bool ok = s->accepts_as_bound_paper_column (this);
   if (ok)
     {
       // Signal that this column needs to be kept alive. They need to be kept
       // alive to have meaningful position and linebreaking.  [maybe we should
       // try keeping all columns alive?, and perhaps inherit position from
       // their (non-)musical brother]
@@ skipping 96 matching lines @@
 
   for (LEFT_and_RIGHT (d))
     {
       Skyline_pair *sp = unsmob<Skyline_pair> (cols[d]->get_property ("horizontal-skylines"));
       if (sp)
         skys[d] = (*sp)[-d];
     }
 
   skys[RIGHT].merge (Separation_item::conditional_skyline (right, left));
 
-  return max (0.0, skys[LEFT].distance (skys[RIGHT]));
+  return std::max (0.0, skys[LEFT].distance (skys[RIGHT]));
 }
 
 Interval
 Paper_column::break_align_width (Grob *me, SCM align_syms)
 {
   Grob *p = me->get_parent (X_AXIS);
 
   if (scm_is_symbol (align_syms))
     align_syms = scm_list_1 (align_syms);
 
@@ skipping 296 matching lines @@
                "page-break-penalty "
                "page-break-permission "
                "page-turn-penalty "
                "page-turn-permission "
                "rhythmic-location "
                "shortest-playing-duration "
                "shortest-starter-duration "
                "spacing "
                "used "
                "when ");