mesa@23.1.4: missing symbols

[Sergio Pastor Pérez]

Hi.

I've noticed that the `mesa' package we provide is missing some
symbols that according to the OpenGL specification should be present on
the `libGL.so.1` library.

The following commands demonstrate the issue:
--8<---------------cut here---------------start------------->8---
$ guix build mesa
/gnu/store/ds15k8bzqf1m861w17hshd8i54pffig9-mesa-23.1.4-bin
/gnu/store/hxvp1sp897rnnpbpb0xk887m4822gf77-mesa-23.1.4

$ nm -gD /gnu/store/hxvp1sp897rnnpbpb0xk887m4822gf77-mesa-23.1.4/lib/libGL.so.1 
| grep glBindTextureUnit

$ glxinfo | grep "OpenGL version"
OpenGL version string: 4.6 (Compatibility Profile) Mesa 23.1.4
--8<---------------cut here---------------end--------------->8---

As you can see the grep does not match any symbol. In contrast, if we do
the same under an Ubuntu installation, we can see the following output:
--8<---------------cut here---------------start------------->8---
$ nm -gD /usr/lib/x86_64-linux-gnu/libGL.so.1 | grep glBindTextureUnit
0000000000046b60 T glBindTextureUnit
0000000000046b80 T glBindTextureUnitParameterEXT

$ glxinfo | grep "OpenGL version"
OpenGL version string: 4.6 (Compatibility Profile) Mesa 23.0.4-0ubuntu1~22.04.1
--8<---------------cut here---------------end--------------->8---

This symbol is also present on the `libGL.so.1` provided by the
proprietary Nvidia driver:
--8<---------------cut here---------------start------------->8---
$ guix build nvidia-driver
/gnu/store/8xhdq3rf9k80n6vz5cwi7z1dg5wjq002-nvidia-driver-515.76

$ nm -gD 
/gnu/store/8xhdq3rf9k80n6vz5cwi7z1dg5wjq002-nvidia-driver-515.76/lib/libGL.so.1 
| grep glBindTextureUnit
00000000000476c0 T glBindTextureUnit
0000000000047700 T glBindTextureUnitParameterEXT

$ glxinfo | grep "OpenGL version"
OpenGL version string: 4.5 (Compatibility Profile) Mesa 23.1.4
--8<---------------cut here---------------end--------------->8---

I've noticed the problem because I'm packaging a rust up that I wanted to
contribute as an example on how to build applications that use meson to
build rust packages. This app uses `rust-minidl' to load `libGL.so.1` at
runtime. The app tries to use the `glBindTextureUnit` symbol and panics.

Does anyone know why this symbol could be missing? Could we fix the
`mesa' package? I would like users of the open source drivers to be able
to run the package.

Thanks,
Sergio.