Bug#963987: buster-pu: package libtool/2.4.6-9

[Wang Shanker <shankerwangmiao@gmail.com>]

Hi, all

I meet the same problem when building the latest qemu package 
on buster. The output of the failed build log is :

```
.....
powerpc64-linux-gnu-ar cru libfs.a  xxx.o xxx.o (a lot of .o's omitted); powerpc64-linux-gnu-ranlib libfs.a
powerpc64-linux-gnu-ar: `u' modifier ignored since `D' is the default (see `U')
cc1: all warnings being treated as errors
make[1]: *** [rules.mak:233: target/drivers/usbohci.o] Error 1
make[1]: *** Waiting for unfinished jobs....
```

It seems that the problem is related to the option `cru` to ar
at first look. However, it's not the case. Rhe cause of the 
build failure is actually in usbohci.c: 

```
/home/xxxx/qemu/qemu/qemu-6.0+dfsg/roms/openbios/drivers/usbohci.c:46:32: error: unknown option after '#pragma GCC diagnostic' kind [-Werror=pragmas]
 #pragma GCC diagnostic warning "-Waddress-of-packed-member"
                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
```

That's because the option `-Waddress-of-packed-member` is introduced
in gcc 9, and we only have gcc 8 on buster.

I'm posting this information here, in case anyone should reach this
bug report via search engine.

Cheers,

Miao Wang