Fix crash when surfaces fail to allocate

src/engine/surface_load.c

@@ -71,6 +71,7 @@ static struct Surface *alloc_surface(void) {
     //  we, um...
     // Perhaps originally just debug feedback?
     if (gSurfacesAllocated >= sSurfacePoolSize) {
+        return NULL;
     }
 
     surface->type = 0;
@@ -363,6 +364,7 @@ static struct Surface *read_surface_data(s16 *vertexData, s16 **vertexIndices) {
     nz *= mag;
 
     surface = alloc_surface();
+    if (surface == NULL) { return NULL; }
 
     vec3s_copy(surface->prevVertex1, surface->vertex1);
     vec3s_copy(surface->prevVertex2, surface->vertex2);

src/pc/lua/smlua_obj_utils.c

@@ -22,6 +22,7 @@ static struct Object* spawn_object_internal(enum BehaviorId behaviorId, enum Mod
     }
 
     struct Object* obj = spawn_object(gMarioStates[0].marioObj, loadedModelId, behavior);
+
     if (obj == NULL) {
         LOG_ERROR("failed to allocate object");
         return NULL;