https://bugs.gentoo.org/937853

--- a/font_freetype/agg_font_freetype.cpp
+++ b/font_freetype/agg_font_freetype.cpp
@@ -186,7 +186,7 @@
             v_control = v_start;
 
             point = outline.points + first;
-            tags  = outline.tags  + first;
+            tags  = reinterpret_cast<char*>(outline.tags) + first;
             tag   = FT_CURVE_TAG(tags[0]);
 
             // A contour cannot start with a cubic control point!