https://bugs.freedesktop.org/show_bug.cgi?id=79659
--- Comment #1 from Michel Dänzer michel@daenzer.net --- Looks like it's failing to compile some (all?) fragment shaders:
GLShader::loadFragment(): error in "core/shaders/default/sky/fragment_volume_ambient.shader" file defines: UNKNOWN,QUALITY_LOW,QUALITY_MEDIUM,QUALITY_HIGH,MULTISAMPLE_0,USE_INSTANCING,USE_GEOMETRY_SHADER,USE_TEXTURE_3D,USE_TEXTURE_ARRAY,USE_ALPHA_FADE,USE_REFLECTION,USE_OCCLUSION,HAS_DEFERRED_COLOR,HAS_DEFERRED_NORMAL,USE_RGB10A2,USE_ENVIRONMENT,USE_NORMALIZATION,USE_DIRECTIONAL_LIGHTMAPS,USE_SHADOW_KERNEL,OPENGL,HAS_ARB_DRAW_INSTANCED,HAS_ARB_TEXTURE_SNORM,SHADING_LANGUAGE=330,USE_ARB_BLEND_FUNC_EXTENDED,USE_ARB_SHADER_BIT_ENCODING,USE_ARB_SAMPLE_SHADING,,TURBULENCE 0:170(1): error: syntax error, unexpected EXTENSION, expecting $end
... and so on.