https://bugs.gentoo.org/790746
--- a/src/MOGL/MOGL_Fenetre.h
+++ b/src/MOGL/MOGL_Fenetre.h
@@ -52,7 +52,7 @@ class MOGL_Fenetre
   private:
     struct CompareResolution
     {
-        bool operator() (const MOGL_Resolution & x, const MOGL_Resolution & y)
+        bool operator() (const MOGL_Resolution & x, const MOGL_Resolution & y) const
         {
           return x.w < y.w;
         }