Pacify --enable-gcc-warnings when no window system is used.

These warnings found that subscript error, so they seem worthwhile.
* composite.c (char_composable_p): Simplify a bit.
* frame.c (x_set_frame_parameters): Add an IF_LINT.
* frame.c (x_set_horizontal_scroll_bars, x_set_scroll_bar_height):
* frame.h (FRAME_HAS_HORIZONTAL_SCROLL_BARS):
* window.c (set_window_scroll_bars):
Use USE_HORIZONTAL_SCROLL_BARS for simplicity.
* frame.h [! USE_HORIZONTAL_SCROLL_BARS]:
Ignore -Wsuggest-attribute=const.
* window.h (USE_HORIZONTAL_SCROLL_BARS): New macro.
(WINDOW_HAS_HORIZONTAL_SCROLL_BAR): Use it.

1 files changed, 3 insertions, 7 deletions

diff --git a/src/frame.c b/src/frame.c
index 7077d42dd1b..d0e585622e2 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -3002,7 +3002,7 @@ x_set_frame_parameters (struct frame *f, Lisp_Object alist)
   /* If both of these parameters are present, it's more efficient to
      set them both at once.  So we wait until we've looked at the
      entire list before we set them.  */
-  int width, height;
+  int width, height IF_LINT (= 0);
   bool width_change = 0, height_change = 0;
 
   /* Same here.  */
@@ -3771,9 +3771,7 @@ x_set_vertical_scroll_bars (struct frame *f, Lisp_Object arg, Lisp_Object oldval
 void
 x_set_horizontal_scroll_bars (struct frame *f, Lisp_Object arg, Lisp_Object oldval)
 {
-#if (defined (HAVE_WINDOW_SYSTEM)                                       \
-     && ((defined (USE_TOOLKIT_SCROLL_BARS) && !defined (HAVE_NS))      \
-         || defined (HAVE_NTGUI)))
+#if USE_HORIZONTAL_SCROLL_BARS
   if ((NILP (arg) && FRAME_HAS_HORIZONTAL_SCROLL_BARS (f))
       || (!NILP (arg) && !FRAME_HAS_HORIZONTAL_SCROLL_BARS (f)))
     {
@@ -3823,9 +3821,7 @@ x_set_scroll_bar_width (struct frame *f, Lisp_Object arg, Lisp_Object oldval)
 void
 x_set_scroll_bar_height (struct frame *f, Lisp_Object arg, Lisp_Object oldval)
 {
-#if (defined (HAVE_WINDOW_SYSTEM)                                       \
-     && ((defined (USE_TOOLKIT_SCROLL_BARS) && !defined (HAVE_NS))      \
-         || defined (HAVE_NTGUI)))
+#if USE_HORIZONTAL_SCROLL_BARS
   int unit = FRAME_LINE_HEIGHT (f);
 
   if (NILP (arg))