[PATCH] Avoid crash in write_psymtabs_to_index

[Tom Tromey]

>> If I try "save gdb-index" using the executable from
>> gdb.cp/cmpd-minsyms.exp, gdb will crash.  This happens due to a
>> missing NULL check.

Kevin> LGTM.

Thanks, I'm going to check this in, and then the gdb-index patch.

Tom