Optimized include/*.h: (recursively) include all headers needed by
this .h file, but only those. Necessary fixes to a lot of .c files,
started optimizing "windows.h" away from some of them. Moved
GetCurrentTask prototype to wine/winbase16.h.

diff --git a/dlls/msacm/msacm_main.c b/dlls/msacm/msacm_main.c
index e234d43..ea65a5b 100644
--- a/dlls/msacm/msacm_main.c
+++ b/dlls/msacm/msacm_main.c
@@ -4,12 +4,11 @@
  *      Copyright 1998  Patrik Stridvall
  */
 
-#include "windows.h"
 #include "winerror.h"
+#include "winbase.h"
 #include "wintypes.h"
-#include "debug.h"
-#include "mmsystem.h"
 #include "msacm.h"
+#include "debug.h"
 
 /***********************************************************************
  *           ACMGETVERSION (MSACM.7)