ext/mask.c in ruby-vips-0.3.4 vs ext/mask.c in ruby-vips-0.3.5

@@ -280,10 +280,10 @@
         if (imask && dmask)
             errstr = "Expected an array or a Mask";
         else
             errstr = "Expected an int array or an int Mask";
 
-        rb_raise(rb_eArgError, errstr);
+        rb_raise(rb_eArgError, "%s", errstr);
     }
 
     if (imask)
         *imask = imask_t;