Make alsa optional
diff --git a/CMakeLists.txt b/CMakeLists.txt
index ca53957..7305e85 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -165,11 +165,7 @@ if(NOT Boost_FOUND)
 endif()
 find_package(ICU COMPONENTS uc i18n REQUIRED)
 if(UNIX AND NOT APPLE)
-  if(LINUX)
-    find_package(ALSA REQUIRED)
-  else()
-    find_package(ALSA)
-  endif()
+  find_package(ALSA)
   find_package(X11 COMPONENTS X11_xcb)
 endif()
 pkg_check_modules(GLIB REQUIRED IMPORTED_TARGET glib-2.0)