"MODULE already defined" when compiling Android 4.3 source code

Question

I downloaded the newest Android source code with repo, and attempted to compile it. An error message printed when I ran make -j4. Detail following:

build/core/base_rules.mk:130: *** external/webrtc/src/system_wrappers/source: MODULE.TARGET.STATIC_LIBRARIES.libwebrtc_system_wrappers already defined by external/webrtc/src/system_wrappers/source. Stop.

Answer 1

Apparently there is a bug in the webrtc makefiles that causes it to ignore including STL if the NDK_ROOT environmental variable is previously defined (by ~/.bashrc, in my case). So just make sure NDK_ROOT is not defined at all when building. You can temporarily unset it with this command:

unset NDK_ROOT