tweaks: delete some fragments of code that have become irrelevant

Since the previous commit, USE_SLANG can only be defined when NANO_TINY
is also defined.  This means that code that is present only in non-tiny
versions does not need to cater for Slang.

src/nano.c

@@ -1308,7 +1308,7 @@ void regenerate_screen(void)
 
 	/* We could check whether COLS or LINES changed, and return otherwise,
 	 * but it seems curses does not always update these global variables. */
-#if defined(USE_SLANG) || defined(REDEFINING_MACROS_OK)
+#ifdef REDEFINING_MACROS_OK
 	COLS = win.ws_col;
 	LINES = win.ws_row;
 #endif
@@ -1317,19 +1317,10 @@ void regenerate_screen(void)
 	/* Ensure that firstcolumn is the starting column of its chunk. */
 	ensure_firstcolumn_is_aligned();
 
-#ifdef USE_SLANG
-	/* Slang curses emulation brain damage, part 1: If we just do what
-	 * curses does here, it'll only work properly if the resize made the
-	 * window smaller.  Do what mutt does: Leave and immediately reenter
-	 * Slang screen management mode. */
-	SLsmg_reset_smg();
-	SLsmg_init_smg();
-#else
 	/* Do the equivalent of what Minimum Profit does: leave and immediately
 	 * reenter curses mode. */
 	endwin();
 	doupdate();
-#endif
 
 	/* Put the terminal in the desired state again, recreate the subwindows
 	 * with their (new) sizes, and redraw the contents of these windows. */

src/winio.c

@@ -173,9 +173,6 @@ void run_macro(void)
  * in the keystroke buffer. */
 void read_keys_from(WINDOW *win)
 {
-#if defined(USE_SLANG) && !defined(NANO_TINY)
-	bool skip_others = FALSE;
-#endif
 	int input = ERR;
 	size_t errcount = 0;
 
@@ -196,11 +193,7 @@ void read_keys_from(WINDOW *win)
 #ifndef NANO_TINY
 		if (the_window_resized) {
 			regenerate_screen();
-#ifdef USE_SLANG
-			skip_others = TRUE;
-#else
 			input = KEY_WINCH;
-#endif
 		}
 #endif
 		if (input == ERR && !waiting_mode) {
@@ -227,10 +220,6 @@ void read_keys_from(WINDOW *win)
 	/* If we got a SIGWINCH, get out as the win argument is no longer valid. */
 	if (input == KEY_WINCH)
 		return;
-#ifdef USE_SLANG
-	if (skip_others)
-		return;
-#endif
 #endif
 
 	/* Read in the remaining characters using non-blocking input. */