[LyX/2.3.x] Fix Visual C++ warning

[Jean-Marc Lasgouttes]

commit 96ef3d320b66e7daa73d88de548b1bb617cdc1cd
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Mon Feb 11 10:43:59 2019 +0100

    Fix Visual C++ warning
    
    (cherry picked from commit 2215f4c2b43f9c282f35984182dcd958c8a27ced)
---
 src/RowPainter.cpp |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/RowPainter.cpp b/src/RowPainter.cpp
index 93ac63d..f27eae6 100644
--- a/src/RowPainter.cpp
+++ b/src/RowPainter.cpp
@@ -525,9 +525,9 @@ void RowPainter::paintLast() const
                }
 
                if (endlabel == END_LABEL_BOX)
-                       pi_.pain.rectangle(xo_ + x, y, size, size, 
Color_eolmarker);
+                       pi_.pain.rectangle(int(xo_) + x, y, size, size, 
Color_eolmarker);
                else
-                       pi_.pain.fillRectangle(xo_ + x, y, size, size, 
Color_eolmarker);
+                       pi_.pain.fillRectangle(int(xo_) + x, y, size, size, 
Color_eolmarker);
                break;
        }