Re: [Qemu-devel] [PATCH v2] configure: properly check if -lrt and -lm is needed

[Peter Maydell]

On 16 August 2012 14:22, Natanael Copa <address@hidden> wrote:
> Fixes build against uClibc.
>
> uClibc provides 2 versions of clock_gettime(), one with realtime
> support and one without (this is so you can avoid linking in -lrt
> unless actually needed). This means that the clock_gettime() don't
> need -lrt. We still need it for timer_create() so we check for this
> function in addition.
>
> We also need check if -lm is needed for isnan().
>
> Both -lm and -lrt are needed for libs_qga.
>
> Signed-off-by: Natanael Copa <address@hidden>
> ---
> The Xen people have nagged me to get this patch upstream so I have come
> up with a rebased v2 patch after consulting with pm215 on IRC.
>
> Please consider include this.
>
> Changes v1->v2:
>  - Check for sin() in addition to isnan()
>  - Add comment on why we also check for timer_create
>  - Use $LIBS and $libs_qga instead of $libm and $librt, based on
>    feedback from pm215 on IRC
>  - Do not remove the explicit add of -lm unless Haiku. This was due
>    to http://www.mail-archive.com/address@hidden/msg102965.html
>    I am not sure if this is valid, though.

Certainly building a linux-user target works for me even without
that explicit 'LIBS+=-lm' in Makefile.target. Blue, can you remember
what you had in mind when you wrote that email?

thanks
-- PMM