[Asterisk-Users] app_nv_backgrounddetect - how to make module

[Joseph]

How to compile additional module to asterisk?

I have app_nv_backgrounddetect.c file and followed instructions below,
but "make" did not generate app_nv_backgrounddetect.so or
app_nv_backgrounddetect.o

(1) Drop the code in your /usr/src/asterisk/apps directory 
(2) Edit the Makefile in the apps directory. Add the following line: 
   APPS+=app_nv_backgrounddetect.so
(3) Go to /usr/src/asterisk and run "make", then run "make install"

I've noticed that in .../apps directory every module has three files
file_name.c 
file_name.o
file_name.so

How do I get the last two if I have the first one?

-- 
#Joseph