OpenGL: changes in shaderutils * removed superfluous ";" at end of macros * introduced shader defines `*_ENABLED`, e.g. `SHADING_ENABLED`, `GRADIENTS_ENABLED`, `PLANES_ENABLED`
OpenGL: changes in shaderutils
* removed superfluous ";" at end of macros
* introduced shader defines `*_ENABLED`, e.g. `SHADING_ENABLED`, `GRADIENTS_ENABLED`, `PLANES_ENABLED`

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