Backfit commit 'c0bc500620' to SDL1/2:

"Added gamma correction option to the setup menu; bug #977; some work from Nic"

sc2/src/libs/graphics/sdl/sdl1_common.c

@@ -110,17 +110,10 @@ TFB_ReInitGraphics (int driver, int flags, int width, int height)
 	return result;
 }
 
-void
+bool
 TFB_SetGamma (float gamma)
 {
-	if (SDL_SetGamma (gamma, gamma, gamma) == -1)
-	{
-		log_add (log_Warning, "Unable to set gamma correction.");
-	}
-	else
-	{
-		log_add (log_Info, "Gamma correction set to %1.4f.", gamma);
-	}
+	return (SDL_SetGamma (gamma, gamma, gamma) == 0);
 }
 
 int

sc2/src/libs/graphics/sdl/sdl2_common.c

@@ -94,6 +94,7 @@ void
 TFB_SetGamma (float gamma)
 {
 	log_add (log_Warning, "Custom gamma correction is not available in the SDL2 engine.");
+	return 0;
 }
 
 int