bug#17294: Bug - nm_test_func check is confused with -flto

[Martin Liška]

On 05/17/2014 02:46 AM, Peter Rosin wrote:
> On 2014-04-18 15:01, Martin Liška wrote:
> > Hello,
> >      starting with GCC 4.9.0, compiler will use just slim objects files during 
> > LTO compilation. That means, no assembly output is put to object files. I 
> > noticed that libtool uses nm tools to extract symbol from object file: 
> > http://pastebin.com/RF1VubdR. Would it be possible to add -fno-lto for this 
> > check?
> >
> > I think there should be added '-fno-lto' at line 14:
> >    (eval $ac_compile -fno-lto) 2>&5
> >
> > What do you think about that?
> Hi, and sorry for the late response.
>
> I think that it is not possible to blindly add -fno-lto without knowing
> if the compiler understands -fno-lto.
Hello Peter,
    I would appreciate any kind of help connected to configure script to be 
able to support -flto.

My suggestion:
1) we can detect if a compiler supports -flto
2) if so, we can define $ac_compile_without_lto = "$ac_compile -fno-lto"
3) otherwise, $ac_compile_without_lto = $ac_compile

What do you think about it?
Today, I found out another packages suffering from the same problem.

Thanks,
Martin
> Changing this takes more effort, sorry.
>
> Cheers,
> Peter