diff -Naur a/common/multiload-config.c b/common/multiload-config.c
--- a/common/multiload-config.c	2016-12-05 17:13:59.000000000 +0100
+++ b/common/multiload-config.c	2020-07-30 21:18:03.568945194 +0200
@@ -26,6 +26,8 @@
 #include "graph-data.h"
 #include "multiload-config.h"
 
+GraphType graph_types[GRAPH_MAX];
+
 guint multiload_config_get_num_colors(guint id)
 {
 	g_assert_cmpuint (graph_types[id].num_colors, <=, MAX_COLORS);
diff -Naur a/common/multiload-config.h b/common/multiload-config.h
--- a/common/multiload-config.h	2016-12-05 17:13:59.000000000 +0100
+++ b/common/multiload-config.h	2020-07-30 21:18:21.685273529 +0200
@@ -56,7 +56,7 @@
 
 
 // global variable
-GraphType graph_types[GRAPH_MAX];
+extern GraphType graph_types[GRAPH_MAX];
 
 
 G_GNUC_INTERNAL guint