Avoid compilation warnings

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.