patch 8.2.3541: compiler warning for unused variable in tiny version

Problem:    Compiler warning for unused variable in tiny version.
Solution:   Add #ifdef. (John Marriott)
diff --git a/src/highlight.c b/src/highlight.c
index a964acd..76d9a7e 100644
--- a/src/highlight.c
+++ b/src/highlight.c
@@ -1108,7 +1108,9 @@
 	int	*do_colors UNUSED,
 	int	init)
 {
+# if defined(FEAT_GUI) || defined(FEAT_TERMGUICOLORS)
     long	i;
+# endif
     char_u	**namep;
     int		did_change = FALSE;
 
@@ -1175,7 +1177,9 @@
 	int	*do_colors UNUSED,
 	int	init)
 {
+# if defined(FEAT_GUI) || defined(FEAT_TERMGUICOLORS)
     int		i;
+# endif
     char_u	**namep;
     int		did_change = FALSE;