$NetBSD$

Add -lossaudio for NetBSD.

--- avidemux_plugins/ADM_audioDevices/Oss/CMakeLists.txt.orig	2022-09-17 13:59:17.000000000 +0000
+++ avidemux_plugins/ADM_audioDevices/Oss/CMakeLists.txt
@@ -4,6 +4,9 @@ INCLUDE(av_plugin)
 SET(ADM_av_oss_SRCS ADM_deviceoss.cpp)
 
 ADD_AUDIO_DEVICE(ADM_av_oss  ${ADM_av_oss_SRCS})
+if(CMAKE_SYSTEM_NAME STREQUAL "NetBSD")
+    TARGET_LINK_LIBRARIES(ADM_av_oss ossaudio)
+endif()
 include_directories(${OSS_INCLUDE_DIR})
 INIT_AUDIO_DEVICE(ADM_av_oss)
 INSTALL_AUDIO_DEVICE(ADM_av_oss)