Info Panel: use system time to get the current year

Use the system date to get the current year to insert inside the copyright line.
So no need to update that string anymore.

src/dialog.c

@@ -36,6 +36,7 @@
 #include <dirent.h>
 #include <limits.h>
 #include <errno.h>
+#include <time.h>
 
 #ifdef HAVE_MALLOC_H
 #include <malloc.h>
@@ -1153,7 +1154,7 @@ typedef struct {
 #define COPYRIGHT_TEXT  \
     "Copyright \xc2\xa9 1997-2006 Alfredo K. Kojima\n"\
     "Copyright \xc2\xa9 1998-2006 Dan Pascu\n"\
-    "Copyright \xc2\xa9 2013-2020 Window Maker Developers Team"
+    "Copyright \xc2\xa9 2013-%hu Window Maker Developers Team"
 
 static InfoPanel *infoPanel = NULL;
 
@@ -1194,6 +1195,16 @@ void wShowInfoPanel(WScreen *scr)
 	};
 	int wmScaleWidth, wmScaleHeight;
 	int pwidth, pheight;
+	int current_year = 2020;
+	time_t s;
+	struct tm *current_time;
+
+	s = time(NULL);
+	if (s) {
+		current_time = localtime(&s);
+		if (current_time->tm_year > (current_year - 1900))
+			current_year = current_time->tm_year + 1900;
+	}
 
 	if (infoPanel) {
 		if (infoPanel->scr == scr) {
@@ -1276,7 +1287,9 @@ void wShowInfoPanel(WScreen *scr)
 	WMResizeWidget(panel->copyrL, WMScaleX(360), WMScaleY(60));
 	WMMoveWidget(panel->copyrL, WMScaleX(15), WMScaleY(190));
 	WMSetLabelTextAlignment(panel->copyrL, WALeft);
-	WMSetLabelText(panel->copyrL, COPYRIGHT_TEXT);
+
+	snprintf(buffer, sizeof(buffer), COPYRIGHT_TEXT, current_year);
+	WMSetLabelText(panel->copyrL, buffer);
 	font = WMSystemFontOfSize(scr->wmscreen, WMScaleY(11));
 	if (font) {
 		WMSetLabelFont(panel->copyrL, font);