Remove pic flag from cmake file.

[MFraters]

The -fPIC flag should be automatically set by cmake, so there is no need to specify it manually. @bangerth @tjhei

[bangerth]

That seems like the right choice.

[bangerth]

I believe that the problem is that the CMakeLists.txt file builds a static library that is then later used to link into a shared library or PIC executable. There are multiple ways to achieve what you want:

• Make sure cmake knows about this, by setting the appropriate flag -- see https://stackoverflow.com/questions/38296756/what-is-the-idiomatic-way-in-cmake-to-add-the-fpic-compiler-option
• Build a shared library right away.

My personal opinion is that you should be building a shared library as it minimizes link times for downstream projects. But that's just my opinion.

[github-actions]

Benchmark	Main	Feature	Difference (99.9% CI)
Slab interpolation simple none	1.014 ± 0.003 (s=432)	1.021 ± 0.006 (s=455)	+0.6% .. +0.9%
Slab interpolation curved simple none	1.018 ± 0.004 (s=450)	1.022 ± 0.004 (s=435)	+0.3% .. +0.4%
Spherical slab interpolation simple none	1.185 ± 0.007 (s=378)	1.186 ± 0.006 (s=384)	+0.0% .. +0.3%
Slab interpolation simple curved CMS	1.064 ± 0.004 (s=436)	1.061 ± 0.004 (s=414)	-0.3% .. -0.2%
Spherical slab interpolation simple CMS	1.592 ± 0.010 (s=260)	1.592 ± 0.010 (s=308)	-0.2% .. +0.2%
Spherical fault interpolation simple none	1.192 ± 0.010 (s=375)	1.190 ± 0.011 (s=383)	-0.4% .. +0.0%
Cartesian min max surface	2.327 ± 0.018 (s=196)	2.311 ± 0.019 (s=195)	-1.0% .. -0.4%
Spherical min max surface	7.216 ± 0.029 (s=65)	7.238 ± 0.101 (s=62)	-0.3% .. +0.9%

[MFraters]

Thanks for the advice on how to fix this.

My personal opinion is that you should be building a shared library as it minimizes link times for downstream projects. But that's just my opinion.

I personally like the fact that the the library is compiled into the executable, since it make the executable self contained and even allows the executable to be moved, but I can see that shorter linking times may also be nice and maybe be more useful in practice. I would suggest just fixing this now, and move the static vs dynamic library discussion into a separate issue and potentially a separate pull request.

[bangerth]

Yes, these are independent questions.

[bangerth]

This looks correct to me now, and it also seems to work.