Linux specify another clang version to build with plugin

Hi,

is there a way to specify which clang version UE4 should use to build the engine? I’m using Debian 8 without any super user rights (!), which only has clang 3.5 and I need a plugin in Unreal Engine which only works with clang 3.9.

I downloaded 3.9 from clang, but I don’t know how to instruct UE4 to use those binaries to build the engine. I tried to build the plugin with clang 3.5, but it is not working. So I need to tell UE4 to use my binaries, but until now UE4 always takes the system clang 3.5. I tried setting the CC and CXX environment variables to point to the binaries, but it is not working.

Thanks for any help.