what is the best way to port native project into Android App?

I have a project written in C; it has up to six sub-directories with .mk files, a make directory, at least one makefile, and Android.mk files.

I have used Android Studio, ndk, and JNI to build a project which compiles and runs. Now I want to port the above project into it. I have read all the GNU make manual, and know that I can include other make files. My question is would it be better to use gradle to include the make files above, and can I even do it? I have not read the gradle manual yet. It is my understanding that it is a build environment; I am not clear on what are it's differences / similarities with make. And if I can use it to complement make or I just have to pick one and go with it. I did have to edit it to get the JNI project working. My initial goal is to just run the make files in the native project in silent i.e. have them not produce any .o files and see what they do and validate that I am including them; then I want to include all the .c files and build .o files. I know I can do this with include statements in make file and since I have an Android.mk file in my project, I think I can do it through that. But I wonder if in the long run it is better to use gradle. What should I do please?