--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -193,7 +193,7 @@
     list(APPEND INCLUDE_DIRS "/usr/local/include")
   else()
 
-    pkg_search_module(ALSA REQUIRED alsa)
+    pkg_search_module(ALSA alsa)
     if(ALSA_FOUND)
       add_compile_definitions(HAS_ALSA)
     endif(ALSA_FOUND)
