tests/audiomatch: Add missing return code at the end of main()

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 65da5c56e661a839e017db4c51c73d6f3d8a8fcb)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

tests/audiomatch.c

@@ -107,4 +107,6 @@ int main(int argc, char **argv){
         }
     }
     printf("presig: %d postsig:%d c:%7.4f lenerr:%d\n", bestpos, datlen - siglen - bestpos, bestc / sigamp, datlen - siglen);
+
+    return 0;
 }