allow window title to be set at runtime with -T option

options.c

@@ -31,8 +31,8 @@ const opt_t *options = (const opt_t*) &_options;
 void print_usage(void)
 {
 	printf("usage: sxiv [-abcfhiopqrtvZ] [-A FRAMERATE] [-e WID] [-G GAMMA] "
-	       "[-g GEOMETRY] [-N NAME] [-n NUM] [-S DELAY] [-s MODE] [-z ZOOM] "
-	       "FILES...\n");
+	       "[-g GEOMETRY] [-N NAME] [-T TITLE] [-n NUM] [-S DELAY] [-s MODE] "
+	       "[-z ZOOM] FILES...\n");
 }
 
 void print_version(void)
@@ -66,13 +66,14 @@ void parse_options(int argc, char **argv)
 	_options.hide_bar = false;
 	_options.geometry = NULL;
 	_options.res_name = NULL;
+        _options.title = NULL;
 
 	_options.quiet = false;
 	_options.thumb_mode = false;
 	_options.clean_cache = false;
 	_options.private_mode = false;
 
-	while ((opt = getopt(argc, argv, "A:abce:fG:g:hin:N:opqrS:s:tvZz:")) != -1) {
+	while ((opt = getopt(argc, argv, "A:abce:fG:g:hin:N:opqrS:s:tT:vZz:")) != -1) {
 		switch (opt) {
 			case '?':
 				print_usage();
@@ -149,6 +150,9 @@ void parse_options(int argc, char **argv)
 					error(EXIT_FAILURE, 0, "Invalid argument for option -s: %s", optarg);
 				_options.scalemode = s - scalemodes;
 				break;
+			case 'T':
+				_options.title = optarg;
+				break;
 			case 't':
 				_options.thumb_mode = true;
 				break;

sxiv.h

@@ -279,6 +279,7 @@ struct opt {
 	long embed;
 	char *geometry;
 	char *res_name;
+	char *title;
 
 	/* misc flags: */
 	bool quiet;

window.c

@@ -238,7 +238,7 @@ void win_open(win_t *win)
 	}
 	free(icon_data);
 
-	win_set_title(win, "sxiv");
+	win_set_title(win, options->title != NULL ? options->title : "sxiv");
 
 	classhint.res_class = RES_CLASS;
 	classhint.res_name = options->res_name != NULL ? options->res_name : "sxiv";