test not only if header frei0r.h exists, also use an item
[melted] / src / modules / sox /
drwxr-xr-x   ..
-rw-r--r-- 619 Makefile
-rwxr-xr-x 887 configure
-rw-r--r-- 1131 factory.c
-rw-r--r-- 13360 filter_sox.c