Android NDK: WARNING:/Users/admin/projects/softphone/app/src/main/jni/Android.mk:silkcommon: LOCAL_LDLIBS is always ignored for static libraries

Question

Trying to compile a modified version of SipDroid with Android Studio but I keep getting:

Execution failed for task ':app:buildNdkBuildDebug[armeabi-v7a]'.
> com.android.ide.common.process.ProcessException: Android NDK: WARNING:/Users/admin/projects/softphone/app/src/main/jni/Android.mk:silkcommon: LOCAL_LDLIBS is always ignored for static libraries    
  make: Nothing to be done for 'bv16_jni'.
  make: Nothing to be done for 'g722_jni'.
  [armeabi-v7a] Compile arm    : gsm_jni <= gsm0610_lpc.c

Here's the Android.mk file: https://raw.githubusercontent.com/i-p-tel/sipdroid/master/app/src/main/jni/Android.mk

Project Structure Modules:

I do see this error in my Android.mk file:

Unfortunately there is not much about this error to be found. Hope someone with better knowledge could help me out here.

Thanks in advance!