windows: move INLINE macro, remove UNUSED

Move the INLINE macro from src/uv-common.h to src/win/internal.h, it's
not used in src/unix/ or src/

Remove the UNUSED macro. It's, well, unused.

src/uv-common.h

@@ -40,21 +40,11 @@
 #include "tree.h"
 #include "queue.h"
 
-
 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
 
 #define container_of(ptr, type, member) \
   ((type *) ((char *) (ptr) - offsetof(type, member)))
 
-#ifdef _MSC_VER
-# define UNUSED /* empty */
-# define INLINE __inline
-#else
-# define UNUSED __attribute__((unused))
-# define INLINE inline
-#endif
-
-
 #ifndef _WIN32
 enum {
   UV__HANDLE_INTERNAL = 0x8000,

src/win/internal.h

@@ -29,6 +29,11 @@
 #include "winapi.h"
 #include "winsock.h"
 
+#ifdef _MSC_VER
+# define INLINE __inline
+#else
+# define INLINE inline
+#endif
 
 /*
  * Handles