Patch to cmake detect OpenMP

[Otacílio de Araújo Ramos Neto]

Em ter, 20 de set de 2016 04:04, Matthieu Volat <mazhe at alkumuna.eu>
escreveu:

> On Tue, 20 Sep 2016 00:55:44 -0300
> Otacílio <otacilio.neto at bsd.com.br> wrote:
>
> > I'm trying to port flann (http://www.cs.ubc.ca/research/flann/) to
> > FreeBSD, but I need that cmake detects OpenMP. Unhappy, cmake do not
> > detects OpenMP even when devel/openmp is installed,  so I did this patch
> > to cmake port. What you guys think about? Can I open a bug report with
> > patch?
> >
> > []'s
> >
>
> Hi, are you planning to submit this patch for cmake in ports or the
> upstream project?
>
> This is not a really good idea to hardcode /usr/local like that, for there
> can be may more providers for libomp (lang/clangXY ports, if you need a
> specific to workaround bugs for example... or even maybe base in the
> future?). Also, it would break cmake with GCC.
>
> Without changing any upstream code in either cmake or flann, for FreeBSD
> 11+, you can just set :
>
>   USES+=          compiler:openmp
>   CFLAGS+= -I${LOCALBASE}/include
>   LDFLAGS+= -L${LOCALBASE}/lib -lomp -lm
>
> I did not test how this behave on older release yet... And if you need to
> build cmake-based projects outside ports, here's the flags I use:
>
>  -DCMAKE_REQUIRED_INCLUDES="/usr/local/include" \
>  -DCMAKE_REQUIRED_LIBRARIES="-L/usr/local/lib -lomp -lm" \
>  -DCMAKE_EXE_LINKER_FLAGS="-L/usr/local/lib -lomp -lm" \
>  -DCMAKE_MODULE_LINKER_FLAGS="-L/usr/local/lib -lomp -lm" \
>  -DCMAKE_SHARED_LINKER_FLAGS="-L/usr/local/lib -lomp -lm"
>
> -- Matthieu Volat <mazhe at alkumuna.eu>
>

Hi Matthieu.

I was planning to submit this patch in ports but, after yours appointments,
I have declined from the idea. My motivation was  that if cmake proposes
find OpenMP it must find OpenMP. But, my patch is not the right procedure
to do it.

[]'s
-Otacilio

>