[openscenegraph] Fix '_FPOSOFF' has been deprecated

[anton-danielsson]

Summary

Changes to recipe: openscenegraph/3.6.5

Motivation

Fix build error with latest Visual Studio.
_FPOSOFF has been removed.

Details

openscenegraph/OpenSceneGraph#1323
https://github.com/microsoft/vcpkg/pull/38666/files

---

• Read the contributing guidelines
• Checked that this PR is not a duplicate: list of PRs by recipe
• Tested locally with at least one configuration using a recent version of Conan

[anton-danielsson]

Anything more I need to do?

[jcar87]

Thanks @anton-danielsson for your PR.
We are currently reviewing this - as per our patching policy, we do not generally accept changes to C/C++ sources:
https://github.com/conan-io/conan-center-index/blob/master/docs/adding_packages/sources_and_patches.md#policy-on-patches

I can see that this has been reported upstream openscenegraph/OpenSceneGraph#1323 - however, there is no acknowledgement by the maintainers - we simply do not know whether this patch is acceptable or not, whether it has been tested or not, and whether it contains any behaviour changes.

Given that there's evidence of this specific patch being used elsewhere - we may accept it after we get an understanding.

However, our advice in these cases, when a library has not received updates in almost 5 years - would be to discourage any use of the library - problems like this, i.e.: library no longer compiles for newer compiler versions - will continue to happen over time, and we will not be maintaining this much further.
Please read openscenegraph/OpenSceneGraph#1176 - re the maintenance status of this library.

[anton-danielsson]

Ok, I see. We have OSG as a legacy dependency (others might as well). We should probably move to VSG but also needs to be worth the effort.

We use this patch with our own Conan repo but would be nice to also have it upstream I think.