Kernel: Get rid of Unix namespace.

This is no longer needed as the Kernel can stand on its own legs now
and there won't be any conflict with host system data types.

Kernel/UnixTypes.h

@@ -1,12 +1,8 @@
 #pragma once
 
-extern "C" {
-
 #define FD_SETSIZE 64
 struct fd_set { unsigned char bits[FD_SETSIZE / 8];  };
 
-namespace Unix {
-
 #define WNOHANG 1
 
 #define SIG_DFL ((void*)0)
@@ -295,8 +291,3 @@ struct stat {
     time_t    st_mtime;   /* time of last modification */
     time_t    st_ctime;   /* time of last status change */
 };
-
-}
-
-}
-