a bit more -Werror compatability

for clang, fix warnings in drivers/, lib/, servers/, sys/, common/.
by turning off fatal warnings (takes effect if the default is on),
fixing warnings or reducing the warning level.

Change-Id: Ia1b4bc877c879ba783158081b59aa6ebb021a50f

common/dist/zlib/deflate.c

@@ -51,6 +51,10 @@
 
 /* @(#) Id */
 
+#if defined(__minix) && defined(_STANDALONE)
+#include <lib/libkern/libkern.h>
+#endif
+
 #include "deflate.h"
 
 const char deflate_copyright[] =

common/dist/zlib/infback.c

@@ -12,6 +12,10 @@
    inflate_fast() can be used with either inflate.c or infback.c.
  */
 
+#if defined(__minix) && defined(_STANDALONE)
+#include <lib/libkern/libkern.h>
+#endif
+
 #include "zutil.h"
 #include "inftrees.h"
 #include "inflate.h"

common/dist/zlib/inflate.c

@@ -82,6 +82,10 @@
  * The history for versions after 1.2.0 are in ChangeLog in zlib distribution.
  */
 
+#if defined(__minix) && defined(_STANDALONE)
+#include <lib/libkern/libkern.h>
+#endif
+
 #include "zutil.h"
 #include "inftrees.h"
 #include "inflate.h"