HACK to make deferred imposters more-or-less work.

(transplanted from e41d116728dd1e453273047ba7fde9455a1811d4)

indra/newview/app_settings/shaders/class1/deferred/impostorF.glsl

@@ -14,7 +14,7 @@ uniform sampler2D specularMap;
 void main() 
 {
 	vec4 col = texture2D(diffuseMap, gl_TexCoord[0].xy);
-	gl_FragData[0] = vec4(col.rgb, col.a <= 0.5 ? 0.0 : 0.005);
+	gl_FragData[0] = vec4(col.rgb, col != vec4(0,0,0,0));
 	gl_FragData[1] = texture2D(specularMap, gl_TexCoord[0].xy);
-	gl_FragData[2] = vec4(texture2D(normalMap, gl_TexCoord[0].xy).xyz, 0.0);
+	gl_FragData[2] = texture2D(normalMap, gl_TexCoord[0].xy);
 }