Addresses this GCC warning:

ApproxPts2.C: In function 'void CoCoA::ApproxPts::{anonymous}::ConversionToRR(const std::vector<CoCoA::RingElem>&, const std::vector<std::vector<CoCoA::RingElem> >&, CoCoA::ConstRefRingElem, std::vector<CoCoA::RingElem>&, std::vector<std::vector<CoCoA::RingElem> >&, CoCoA::RingElem&, const CoCoA::ring&)':
ApproxPts2.C:82:27: warning: loop variable 'OrigPt' creates a copy from type 'const PointR' {aka 'const std::vector<CoCoA::RingElem>'} [-Wrange-loop-construct]
   82 |         for (const PointR OrigPt: OrigPts)
      |                           ^~~~~~
ApproxPts2.C:82:27: note: use reference type to prevent copying
   82 |         for (const PointR OrigPt: OrigPts)
      |                           ^~~~~~
      |                           &

--- src/AlgebraicCore/ApproxPts2.C.orig	2021-06-01 09:25:16.896464196 -0600
+++ src/AlgebraicCore/ApproxPts2.C	2021-06-01 15:15:01.191398239 -0600
@@ -79,7 +79,7 @@ namespace CoCoA
         for (long i=0; i < dim; ++i)
           tolerance.push_back(QToRR(OrigTolerance[i]));
         pts.clear();
-        for (const PointR OrigPt: OrigPts)
+        for (const PointR& OrigPt: OrigPts)
         {
           PointR NewPt;
           for (long j=0; j < dim; ++j)