Re: [Flightgear-devel] download_and_compile.sh: Build of stable fails since CMake version bump in OSG

[James T. <ja...@fl...>]

> On 17 Aug 2025, at 17:36, bo23--- via Flightgear-devel <fli...@li...> wrote:
> 
> When trying to build stable with the download_and_compile.sh script, the
> build fails with the error attached at the end. I figured out that this
> happens since OSG commit 89ff2847, where the CMake version was bumped to
> 3.12. Upon changing the required version to 3.10, it builds fine again.
> 
> 
> diff --git a/CMakeLists.txt b/CMakeLists.txt
> index 9b9219edc..7f4d35284 100644
> --- a/CMakeLists.txt
> +++ b/CMakeLists.txt
> @@ -14,7 +14,7 @@ set(CMAKE_ALLOW_LOOSE_LOOP_CONSTRUCTS TRUE)
> set_property(GLOBAL PROPERTY USE_FOLDERS ON)
> 
> 
> -CMAKE_MINIMUM_REQUIRED(VERSION 3.12 FATAL_ERROR)
> +CMAKE_MINIMUM_REQUIRED(VERSION 3.10 FATAL_ERROR)
> 
> if(COMMAND cmake_policy)
>     # Works around warnings libraries linked against that don't

I’m guessing this related to the OpenGL VND policy setting, or at least, that’s the only CMake setting I know of that could potentially trigger this.

http://cmake.org.cn/policy/CMP0072.html

And indeed that page says the default changed with CMake 3.11.

Can you confirm you’re deleting the build directory between each of the tests?

We would in principle prefer to use the NEW value, i.e OpenGL symbols come for libOpenGL.so <http://libopengl.so/> as opposed to libGL.so <http://libgl.so/>, but depending on your distro and graphics driver setup I don’t know one achieves this. For me on recent Ubuntu systems it always just worked.

Kind regards,
James