I found a bug in gdb: when using the completion after the cli command
"interpreter-exec", an out-of-bound access occures.

Attached is a patch proposal that fixes it.

There were 2 problems in the original code in file interps.c, function 
interpreter_completer:
- the case of (num_matches == alloced) was not handled. In that case the 
matches list it not terminated by NULL.
- the xrealloc done at the end is useless since the num_matches is 
always <= alloced.

-- 
Denis PILAT