Avoid compilation warnings

* src/w32fns.c (Fx_file_dialog, w32_parse_and_hook_hot_key):
* src/w32term.c (x_draw_glyph_string):
* src/w32fns.c (compute_tip_xy):
* src/w32font.c (w32font_text_extents):
* src/w32menu.c (set_frame_menubar):
* src/search.c (Freplace_match): Avoid compiler warnings in
optimized builds.

src/search.c

@@ -2630,7 +2630,7 @@ since only regular expressions have distinguished subexpressions.  */)
 	  const unsigned char *add_stuff = NULL;
 	  ptrdiff_t add_len = 0;
 	  ptrdiff_t idx = -1;
-	  ptrdiff_t begbyte;
+	  ptrdiff_t begbyte UNINIT;
 
 	  if (str_multibyte)
 	    {

src/w32fns.c

@@ -7159,7 +7159,7 @@ compute_tip_xy (struct frame *f,
 		int width, int height, int *root_x, int *root_y)
 {
   Lisp_Object left, top, right, bottom;
-  int min_x, min_y, max_x, max_y;
+  int min_x = 0, min_y, max_x = 0, max_y;
 
   /* User-specified position?  */
   left = Fcdr (Fassq (Qleft, parms));
@@ -7777,7 +7777,7 @@ value of DIR as in previous invocations; this is standard Windows behavior.  */)
   OPENFILENAMEA * file_details_a = &new_file_details_a.details;
   int use_unicode = w32_unicode_filenames;
   wchar_t *prompt_w;
-  char *prompt_a;
+  char *prompt_a UNINIT;
   int len;
   char fname_ret[MAX_UTF8_PATH];
 #endif /* NTGUI_UNICODE */
@@ -8505,8 +8505,8 @@ w32_parse_and_hook_hot_key (Lisp_Object key, int hook)
 {
   /* Copied from Fdefine_key and store_in_keymap.  */
   register Lisp_Object c;
-  int vk_code;
-  int lisp_modifiers;
+  int vk_code = 0;
+  int lisp_modifiers = 0;
   int w32_modifiers;
   Lisp_Object res = Qnil;
   char* vkname;

src/w32font.c

@@ -436,7 +436,7 @@ w32font_text_extents (struct font *font, unsigned *code,
   int i;
   HFONT old_font = NULL;
   HDC dc = NULL;
-  struct frame * f;
+  struct frame * f UNINIT;
   int total_width = 0;
   WORD *wcode;
   SIZE size;

src/w32menu.c

@@ -267,7 +267,7 @@ set_frame_menubar (struct frame *f, bool first_time, bool deep_p)
   HMENU menubar_widget = f->output_data.w32->menubar_widget;
   Lisp_Object items;
   widget_value *wv, *first_wv, *prev_wv = 0;
-  int i, last_i;
+  int i, last_i = 0;
   int *submenu_start, *submenu_end;
   int *submenu_top_level_items, *submenu_n_panes;
 

src/w32term.c

@@ -2454,7 +2454,7 @@ x_draw_glyph_string (struct glyph_string *s)
                     thickness = font->underline_thickness;
                   else
                     thickness = 1;
-                  if (x_underline_at_descent_line)
+                  if (x_underline_at_descent_line || !font)
                     position = (s->height - thickness) - (s->ybase - s->y);
                   else
                     {
@@ -2467,9 +2467,9 @@ x_draw_glyph_string (struct glyph_string *s)
                          ROUND (x) = floor (x + 0.5)  */
 
                       if (x_use_underline_position_properties
-                          && font && font->underline_position >= 0)
+                          && font->underline_position >= 0)
                         position = font->underline_position;
-                      else if (font)
+                      else
                         position = (font->descent + 1) / 2;
                     }
                   position = max (position, underline_minimum_offset);