eliminate double-free of tpreserved

src/lib/notcurses.c

@@ -1262,7 +1262,7 @@ notcurses* notcurses_core_init(const notcurses_options* opts, FILE* outfp){
 err:
   logpanic("Alas, you will not be going to space today.\n");
   fbuf_free(&ret->rstate.f);
-  if(ret->tcache.tpreserved){
+  if(ret->tcache.ttyfd >= 0 && ret->tcache.tpreserved){
     (void)tcsetattr(ret->tcache.ttyfd, TCSAFLUSH, ret->tcache.tpreserved);
     free(ret->tcache.tpreserved);
   }

src/lib/termdesc.c

@@ -921,8 +921,9 @@ int interrogate_terminfo(tinfo* ti, const char* termtype, FILE* out, unsigned ut
 err:
   if(ti->tpreserved){
     (void)tcsetattr(ti->ttyfd, TCSANOW, ti->tpreserved);
+    free(ti->tpreserved);
+    ti->tpreserved = NULL;
   }
-  free(ti->tpreserved);
   free(ti->esctable);
   free(ti->termversion);
   del_curterm(cur_term);