patch 9.0.0694: no native sound support on Mac OS

Problem:    No native sound support on Mac OS.
Solution:   Add sound support for Mac OS. (Yee Cheng Chin, closes #11274)
diff --git a/src/vim.h b/src/vim.h
index 4a77dec..57368f3 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -163,9 +163,16 @@
  */
 #include "feature.h"
 
-#if defined(MACOS_X_DARWIN) && defined(FEAT_NORMAL) \
-	&& !defined(FEAT_CLIPBOARD)
-# define FEAT_CLIPBOARD
+#if defined(MACOS_X_DARWIN)
+# if defined(FEAT_NORMAL) && !defined(FEAT_CLIPBOARD)
+#  define FEAT_CLIPBOARD
+# endif
+# if defined(FEAT_BIG) && !defined(FEAT_SOUND)
+#  define FEAT_SOUND
+# endif
+# if defined(FEAT_SOUND)
+#  define FEAT_SOUND_MACOSX
+# endif
 #endif
 
 // +x11 is only enabled when it's both available and wanted.