Fix building without math but with X11

doc/docs.xml

@@ -76,7 +76,11 @@
 			the other libs required (depending on your configure
 			options). You should be able to see which extra packages
 			you need to install by reading errors that you get from
-			'./configure'.
+			'./configure'. You can enable/disable stuff by giving
+			options to configure, but be careful with disabling. For
+			example: with --disable-math you won't get errors but
+			logarithmic graphs will be normal graphs and gauges
+			will miss their line. 
 		</para>
 		<para>Conky has (for some time) been available in the
 			repositories of most popular distributions. Here are some

src/conky.c

@@ -6522,8 +6522,10 @@ static void draw_line(char *s)
 				{
 					int h, by = 0;
 					unsigned long last_colour = current_color;
+#ifdef MATH
 					float angle, px, py;
 					int usage;
+#endif /* MATH */
 
 					if (cur_x - text_start_x > maximum_width
 							&& maximum_width > 0) {

src/specials.c

@@ -254,11 +254,11 @@ static void graph_append(struct special_t *graph, double f, char showaslog)
 {
 	int i;
 
-#ifdef MATH
 	if (showaslog) {
+#ifdef MATH
 		f = log10(f + 1);
-	}
 #endif
+	}
 	
 	if (!graph->scaled && f > graph->graph_scale) {
 		f = graph->graph_scale;