It crashes on FreeBSD 11.2 at the place where the arrow is:
659│ /* create new wavetable object */
660├─> if (type && (root->wavetbl = g_object_new (type, NULL)))
661│ {
662│ swami_object_set (root->wavetbl, "name", "FluidSynth1", NULL);
663│ swami_root_add_object (SWAMI_ROOT (root), G_OBJECT (root->wavetbl));
664│ }
665│ }
The crash occurs in g_type_fundamental called from g_object_new.