[sane-devel] Canon PIXMA 490 Seg Fault

[Atom Mac]

Setting the `SANE_DEBUG_PIXMA` env variable and running `scanimage` with
all of the arguments included in my original post (ex. for the doc
feeder, etc.) causes `scanimage` to immediately exit and print
`Segmentation Fault`.  This differs from when the env variable is unset,
which seems to cause a delay before the seg fault occurs.

I'm a noob when it comes to gdb but assuming I captured the stack trace
correctly, what I'm seeing is:

```
(gdb) exec-file scanimage \
        --device=pixma:04A91787_77BF9D \
        --source="Automatic Document Feeder" \
        --batch=out%d.png \
        --format=png \
        --mode=Gray \
        -vvvvvv
(gdb) run
Starting program: /usr/local/bin/scanimage scanimage \
        --device=pixma:04A91787_77BF9D \
        --source="Automatic Document Feeder" \
        --batch=out%d.png \
        --format=png \
        --mode=Gray \
        -vvvvvv

Program received signal SIGSEGV, Segmentation fault.
0x76fa11fc in memchr () from /lib/ld-musl-armhf.so.1
(gdb) bt
#0  0x76fa11fc in memchr () from /lib/ld-musl-armhf.so.1
#1  0x76fa2114 in strnlen () from /lib/ld-musl-armhf.so.1
#2  0x76f6ae9c in ?? () from /lib/ld-musl-armhf.so.1
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
````