$NetBSD$

--- src/chart.c.orig	2004-08-31 16:34:23.000000000 +0200
+++ src/chart.c
@@ -1086,9 +1086,9 @@ gkrellm_draw_chart_text(GkrellmChart *cp
 				ts = ts_alt;
 				shadow = ts_alt->effect ? 1 : 0;
 				}
-			else if (c == 'x' && isdigit(*s))
+			else if (c == 'x' && isdigit((unsigned char)*s))
 				xx = *s++ - '0';
-			else if (c == 'y' && isdigit(*s))
+			else if (c == 'y' && isdigit((unsigned char)*s))
 				y = *s++ - '0';
 			else if (c == 'D')
 				{
