Fix issue with shader preprocessor variables

files/shaders/lighting.glsl

@@ -14,7 +14,7 @@ void perLight(out vec3 ambientOut, out vec3 diffuseOut, int lightIndex, vec3 vie
     diffuseOut = diffuse.xyz * gl_LightSource[lightIndex].diffuse.xyz * max(dot(viewNormal.xyz, lightDir), 0.0) * illumination;
 }
 
-#ifdef PER_PIXEL_LIGHTING
+#if PER_PIXEL_LIGHTING
 vec4 doLighting(vec3 viewPos, vec3 viewNormal, vec4 vertexColor, float shadowing)
 #else
 vec4 doLighting(vec3 viewPos, vec3 viewNormal, vec4 vertexColor, out vec3 shadowDiffuse)