Implementation of curve mapping in GLSL

The title says it all, now having curve mapping
enabled in color management settings wouldn't
force fallback from GLSL to CPU based color space
conversion.

intern/opencolorio/fallback_impl.cc

@@ -418,7 +418,8 @@ bool FallbackImpl::supportGLSLDraw(void)
 	return false;
 }
 
-bool FallbackImpl::setupGLSLDraw(struct OCIO_GLSLDrawState ** /*state_r*/, OCIO_ConstProcessorRcPtr * /*processor*/, bool /*predivide*/)
+bool FallbackImpl::setupGLSLDraw(struct OCIO_GLSLDrawState ** /*state_r*/, OCIO_ConstProcessorRcPtr * /*processor*/,
+                                 OCIO_CurveMappingSettings * /*curve_mapping_settings*/, bool /*predivide*/)
 {
 	return false;
 }