[bug-gawk] Core dump in gawk 4.2.0

[Jeremy Feusi]

Hi,
I am working on a project for school in which I use afl to find bugs in
software and I decided to fuzz gawk. In doing so I disovered a segfault
in r_interpret(). Running gdb it appears that on line 140 of interpret.h
there is an attempt to access a null address.
command:
gawk '!_""' <file>
where <file> is a file containing at least on character.

result:
gawk: cmd. line:1: (FILENAME=<file> FNR=1) fatal error: internal error
Aborted (core dumped)

I am using gawk 4.2.0 on arch linux.
cheers
Jeremy