[clipboard] Added "ui.clipboard_file" to add text to the system clipboard.

ui.clipboard_file is filename of the clipboard file. This file can be a named pipe.
See contrib/clipboard/clip.sh how to set up copying to clipboard using socat and xclip.
Just run clip.sh (it will be running in a loop) before starting elinks and
set ui.clipboard_file = "~/.elinks/clipboard.fifo".

contrib/clipboard/clip.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+trap exit SIGTERM SIGINT
+
+while true
+do
+	socat -u PIPE:$HOME/.elinks/clipboard.fifo EXEC:"xclip -sel clip"
+done

src/config/options.inc

@@ -1459,6 +1459,10 @@ static union option_info config_options_info[] = {
 		N_("Keep the session active even if the last terminal "
 		"exits.")),
 
+	INIT_OPT_STRING("ui", N_("Clipboard file"),
+		"clipboard_file", 0, "",
+		N_("Filename of the clipboard file.")),
+
 #ifdef HAVE_STRFTIME
 	INIT_OPT_STRING("ui", N_("Date format"),
 		"date_format", 0, "%b %e %H:%M",

src/osdep/osdep.c

@@ -67,11 +67,13 @@
 
 #include "elinks.h"
 
+#include "config/options.h"
 #include "main/select.h"
 #include "osdep/osdep.h"
 #include "osdep/signals.h"
 #include "terminal/terminal.h"
 #include "util/conv.h"
+#include "util/file.h"
 #include "util/memory.h"
 #include "util/string.h"
 
@@ -403,6 +405,26 @@ get_clipboard_text(void)
 void
 set_clipboard_text(unsigned char *data)
 {
+	unsigned char *f = get_opt_str("ui.clipboard_file", NULL);
+
+	if (f && *f) {
+		unsigned char *filename = expand_tilde(f);
+
+		if (filename) {
+#ifdef HAVE_ACCESS
+			if (access(filename, W_OK) >= 0) {
+				FILE *out = fopen(filename, "a");
+
+				if (out) {
+					fputs(data, out);
+					fclose(out);
+				}
+			}
+#endif
+			mem_free(filename);
+		}
+	}
+
 	/* GNU Screen's clipboard */
 	if (is_gnuscreen()) {
 		struct string str;