OpenGL2: Add r_glossIsRoughness.

code/renderergl2/tr_glsl.c

@@ -1025,6 +1025,9 @@ void GLSL_InitGPUShaders(void)
 		if (r_specularIsMetallic->value)
 			Q_strcat(extradefines, 1024, "#define SPECULAR_IS_METALLIC\n");
 
+		if (r_glossIsRoughness->value)
+			Q_strcat(extradefines, 1024, "#define GLOSS_IS_ROUGHNESS\n");
+
 		if (r_dlightMode->integer >= 2)
 			Q_strcat(extradefines, 1024, "#define USE_SHADOWMAP\n");