Geometry shaders not working for OpenGL on Linux

Currently there's two issues with geometry shaders:

• The Cg system doesn't translate HLSL to GLSL with geometry shaders (any target greater than 3 just results in "No subshaders can run on this graphics card"
• GLSLPROGRAM only does VERTEX and FRAGMENT passes, so specifying a geometry shader manually is also impossible

My graphics card supports all the way up to shader level 5 in GLSL (it has GL_ARB_gpu_shader5 and GL_ARB_geometry_shader4 listed as supported in glxinfo).

I'd settle for GLSLPROGRAM supporting a GEOMETRY pass so that this was at least possible manually, but according to the Cg website, translation to OpenGL geometry shaders are supported in the toolkit: https://developer.nvidia.com/cg-profiles (tessellation shaders are also supported).

 

We don't support geometry (nor tessellation) shaders with the current OpenGL backend (neither Linux nor OSX).
We should be able to support them with the new backend, which is an option for Windows in Unity 5.1, will be an option for Linux in Unity 5.2, and should be available for OSX in 5.3.