The OSS4 backend doesn't currently work on FreeBSD. Use the OSS3 backend
as a fallback instead.

PR: 273476

--- CMakeLists.txt.orig	2024-01-09 20:14:13 UTC
+++ CMakeLists.txt
@@ -126,7 +126,7 @@ if (HAVE_SOUNDCARD_H OR HAVE_SYS_SOUNDCARD_H)
 
   if (${TEST_COMPILE_RESULT} AND (${TEST_RUN_RESULT} EQUAL 0))
     message(STATUS "Detected OSS version ${TEST_RESULT_VERSION}")
-    if (${TEST_RESULT_VERSION} GREATER_EQUAL 0x040000)
+    if (${TEST_RESULT_VERSION} GREATER_EQUAL 0x040000 AND NOT CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
       message(STATUS "Building with OSS 4 support")
       set(HAVE_OSS_4 true)
       add_definitions(-DHAVE_OSS_4)