Turn SvgMarkerNode::MarkerUnits into scoped enum

...to avoid -Werror,-Wshadow from Clang trunk with
<https://reviews.llvm.org/D52400> "Improve -Wshadow warnings with enumerators",
warning about shadowing of userSpaceOnUse in enum SvgUnits in
svgio/inc/svgtools.hxx

Change-Id: Ie1438e6ad0f73c73ad643157e5f8366a6e3f6851
Reviewed-on: https://gerrit.libreoffice.org/61933
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

svgio/inc/svgmarkernode.hxx

@@ -31,7 +31,7 @@ namespace svgio
         class SvgMarkerNode : public SvgNode
         {
         public:
-            enum MarkerUnits
+            enum class MarkerUnits
             {
                 strokeWidth,
                 userSpaceOnUse

svgio/source/svgreader/svgmarkernode.cxx

@@ -32,7 +32,7 @@ namespace svgio
             maSvgAspectRatio(),
             maRefX(0),
             maRefY(0),
-            maMarkerUnits(strokeWidth),
+            maMarkerUnits(MarkerUnits::strokeWidth),
             maMarkerWidth(3),
             maMarkerHeight(3),
             mfAngle(0.0),
@@ -106,11 +106,11 @@ namespace svgio
                     {
                         if(aContent.startsWith("strokeWidth"))
                         {
-                            setMarkerUnits(strokeWidth);
+                            setMarkerUnits(MarkerUnits::strokeWidth);
                         }
                         else if(aContent.match(commonStrings::aStrUserSpaceOnUse))
                         {
-                            setMarkerUnits(userSpaceOnUse);
+                            setMarkerUnits(MarkerUnits::userSpaceOnUse);
                         }
                     }
                     break;

svgio/source/svgreader/svgstyleattributes.cxx

@@ -832,7 +832,7 @@ namespace svgio
                 {
                     double fTargetWidth(rMarker.getMarkerWidth().isSet() ? rMarker.getMarkerWidth().solve(mrOwner, xcoordinate) : 3.0);
                     double fTargetHeight(rMarker.getMarkerHeight().isSet() ? rMarker.getMarkerHeight().solve(mrOwner, xcoordinate) : 3.0);
-                    const bool bStrokeWidth(SvgMarkerNode::strokeWidth == rMarker.getMarkerUnits());
+                    const bool bStrokeWidth(SvgMarkerNode::MarkerUnits::strokeWidth == rMarker.getMarkerUnits());
                     const double fStrokeWidth(getStrokeWidth().isSet() ? getStrokeWidth().solve(mrOwner) : 1.0);
 
                     if(bStrokeWidth)