input: set mouse area by default for all input

Otherwise, mouse button bindings added by mp.add_key_binding() would be
ignored.

It's possible that this "breaks" some older scripts using undocumented
Lua script functions, but it should be safe otherwise.

Fixes #1283.

input/input.c

@@ -362,6 +362,8 @@ static struct cmd_bind_section *get_bind_section(struct input_ctx *ictx,
     }
     *bind_section = (struct cmd_bind_section) {
         .section = bstrdup0(bind_section, section),
+        .mouse_area = {INT_MIN, INT_MIN, INT_MAX, INT_MAX},
+        .mouse_area_set = true,
     };
     return bind_section;
 }
@@ -1223,7 +1225,6 @@ struct input_ctx *mp_input_init(struct mpv_global *global)
     // Setup default section, so that it does nothing.
     mp_input_enable_section(ictx, NULL, MP_INPUT_ALLOW_VO_DRAGGING |
                                         MP_INPUT_ALLOW_HIDE_CURSOR);
-    mp_input_set_section_mouse_area(ictx, NULL, INT_MIN, INT_MIN, INT_MAX, INT_MAX);
 
     return ictx;
 }

player/lua/defaults.lua

@@ -112,7 +112,7 @@ local function update_key_bindings()
         end
         mp.input_define_section(section, cfg, flags)
         -- TODO: remove the section if the script is stopped
-        mp.input_enable_section(section)
+        mp.input_enable_section(section, "allow-hide-cursor|allow-vo-dragging")
     end
 end