Merge branch 'pull_req' of https://github.com/anthofoxo/stb into working

stb_vorbis.c

@@ -33,6 +33,7 @@
 //    Timur Gagiev       Maxwell Koo         Peter Waller
 //    github:audinowho   Dougall Johnson     David Reid
 //    github:Clownacy    Pedro J. Estebanez  Remi Verschelde
+//    AnthoFoxo
 //
 // Partial history:
 //    1.20    - 2020-07-11 - several small fixes
@@ -3642,8 +3643,12 @@ static int start_decoder(vorb *f)
    f->vendor[len] = (char)'\0';
    //user comments
    f->comment_list_length = get32_packet(f);
-   f->comment_list = (char**)setup_malloc(f, sizeof(char*) * (f->comment_list_length));
-   if (f->comment_list == NULL)                     return error(f, VORBIS_outofmem);
+   f->comment_list = NULL;
+   if (f->comment_list_length > 0)
+   {
+      f->comment_list = (char**) setup_malloc(f, sizeof(char*) * (f->comment_list_length));
+      if (f->comment_list == NULL)                  return error(f, VORBIS_outofmem);
+   }
 
    for(i=0; i < f->comment_list_length; ++i) {
       len = get32_packet(f);