Why Unreal Engine 4.8 's Third Party Lib Never Build

I try to modify the Unreal Engine third-party libraries, but found these third-party library won’t be recompiled.How can I recompile third-party libraries.

Open the corresponding third party VS/Xcode project file in the library source directory and rebuild it using the desired configuration (Debug, Release etc.). Some libraries have a .bat file you can run to rebuild them for all configurations.