How to turn a glibc internal variable into an external resolvable symbol?

[Haizhi Xu]

Hi, all:
I have a glibc internal variable named "__libc_missing_32bit_uids" declared 
in getuid.c
The original delcaration is
int __libc_missing_32bit_uids attribute_hidden = -1;

Now I NEED to turn it into an external symbol. So I changed the above code 
to
int __libc_missing_32bit_uids = 1;
weak_extern (__libc_missing_32bit_uids);

After compile, it does not work as I expected.
>From getuid.os, it seems right...
00000000    w   O   .data   00000004 __libc_missing_32bit_uids

But in libc.so, it is changed to a local variable..
001166d8  l    O  .data 00000004  __libc_missing_32bit_uids

Can anybody tell me what I need to do?  what does the 'O' mean in the 3rd 
column output of objdump?

Thanks a lot.

Haizhi