Add (void) before gmt_getpen

Author: Meghan Jones

src/gmt_support.c

@@ -13539,7 +13539,7 @@ int gmt_getpanel (struct GMT_CTRL *GMT, char option, char *text, struct GMT_MAP_
 	P->radius = GMT->session.u2u[GMT_PT][GMT_INCH] * GMT_FRAME_RADIUS;	/* 6 pt */
 	gmt_init_fill (GMT, &P->fill, -1.0, -1.0, -1.0);			/* Default is no fill unless specified */
 	gmt_init_fill (GMT, &P->sfill, gmt_M_is255 (127), gmt_M_is255 (127), gmt_M_is255 (127));	/* Default if gray shade is used */
-	gmt_getpen (GMT, "thicker,black", &P->pen1);			/* Heavier pen for main outline */
+	(void) gmt_getpen (GMT, "thicker,black", &P->pen1);			/* Heavier pen for main outline */
 	P->pen2 = GMT->current.setting.map_default_pen;			/* Thinner pen for optional inner outline */
 	P->debug_pen = GMT->current.setting.map_default_pen;			/* Thinner pen for optional inner outline */
 	P->gap = GMT->session.u2u[GMT_PT][GMT_INCH] * GMT_FRAME_GAP;	/* Default is 2p */