SIGABRT in text_buffer_iconv on malformed input file

[Nathaniel Beaver]

Steps to reproduce:

$ info -f ./bug_sigabrt.info
gconv.c:73: __gconv: Assertion `outbuf != NULL && *outbuf != NULL' failed.
Aborted (core dumped)

Expected behavior:

info shows an error and exits cleanly.

Actual behavior:

info exits with SIGABRT

Discussion:

This file was generated by afl-fuzz and then hand-edited. I do not claim 
to understand how it triggers the bug in texinfo.

Version:

$ git describe --tags
texinfo-6.6-364-g63711e8c6
$ git rev-parse HEAD
63711e8c6fafe9b3cde2a2d0be507032d7ee7bf6

Sincerely,

Nathaniel Beaver

bug_sigabrt.info.gz
Description: application/gzip

gdb.txt
Description: Text document