1 This patch comes from in-house and has been submitted upstream:

     2 https://savannah.gnu.org/bugs/?48433

     3 

     4 --- groff-1.22.3/src/libs/libbib/index.cpp.org	2014-11-04 17:38:35.183524522 +0900

     5 +++ groff-1.22.3/src/libs/libbib/index.cpp	2016-07-07 09:41:11.572149218 +0900

     6 @@ -158,6 +158,10 @@

     7    }

     8    mtime = sb.st_mtime;

     9    int size = int(sb.st_size);

    10 +  if (size == 0) {

    11 +    error("`%1' is an empty file", name);

    12 +    return 0;

    13 +  }

    14    char *addr;

    15    map_addr = mapread(fd, size);

    16    if (map_addr) {