Cleanup: use 'const' where possible, remove redundant check

intern/ghost/intern/GHOST_SystemWayland.cc

@@ -5543,7 +5543,7 @@ static CLG_LogRef LOG_WL_SEAT = {"ghost.wl.handle.seat"};
 
 static bool gwl_seat_capability_pointer_multitouch_check(const GWL_Seat *seat, const bool fallback)
 {
-  zwp_pointer_gestures_v1 *pointer_gestures = seat->system->wp_pointer_gestures_get();
+  const zwp_pointer_gestures_v1 *pointer_gestures = seat->system->wp_pointer_gestures_get();
   if (pointer_gestures == nullptr) {
     return fallback;
   }

intern/ghost/intern/GHOST_WindowWayland.cc

@@ -1341,7 +1341,7 @@ static void libdecor_frame_handle_configure(libdecor_frame *frame,
       /* These values are cleared after use & will practically always be zero.
        * Read them because it's possible multiple configure calls run before they can be handled.
        */
-      GWL_LibDecor_Window &decor = *win->libdecor;
+      const GWL_LibDecor_Window &decor = *win->libdecor;
       size_next[0] = decor.pending.size[0];
       size_next[1] = decor.pending.size[1];
     }

source/blender/imbuf/IMB_metadata.hh

@@ -39,7 +39,7 @@ void IMB_metadata_free(IDProperty *metadata);
  * \param len: length of value buffer allocated by user.
  * \return 1 (true) if metadata is present and value for the key found, 0 (false) otherwise.
  */
-bool IMB_metadata_get_field(IDProperty *metadata,
+bool IMB_metadata_get_field(const IDProperty *metadata,
                             const char *key,
                             char *value,
                             size_t value_maxncpy);

source/blender/imbuf/intern/metadata.cc

@@ -40,18 +40,16 @@ void IMB_metadata_free(IDProperty *metadata)
   IDP_FreeProperty(metadata);
 }
 
-bool IMB_metadata_get_field(IDProperty *metadata,
+bool IMB_metadata_get_field(const IDProperty *metadata,
                             const char *key,
                             char *value,
                             const size_t value_maxncpy)
 {
-  IDProperty *prop;
-
   if (metadata == nullptr) {
     return false;
   }
 
-  prop = IDP_GetPropertyFromGroup(metadata, key);
+  IDProperty *prop = IDP_GetPropertyFromGroup(metadata, key);
 
   if (prop && prop->type == IDP_STRING) {
     BLI_strncpy(value, IDP_String(prop), value_maxncpy);
@@ -82,7 +80,7 @@ void IMB_metadata_set_field(IDProperty *metadata, const char *key, const char *v
   if (prop) {
     IDP_AssignString(prop, value);
   }
-  else if (prop == nullptr) {
+  else {
     prop = IDP_NewString(value, key);
     IDP_AddToGroup(metadata, prop);
   }