Move shared headers in common/include

Headers that will be shared between old includes and NetBSD-like includes
are moved into common/include tree. They are still copied in /usr/include
in 'make includes', so compilation and programs aren't be affected.

include/sys/mount.h

@@ -1,24 +0,0 @@
-/* <sys/mount.h>
- * definitions for mount(2) 
- */
-
-#ifndef _MOUNT_H
-#define _MOUNT_H
-
-#define MS_RDONLY	0x001	/* Mount device read only */
-#define MS_REUSE	0x002	/* Tell RS to try reusing binary from memory */
-#define MS_LABEL16	0x004	/* Mount message points to 16-byte label */
-#define MS_EXISTING	0x008	/* Tell mount to use already running server */
-
-
-/* Function Prototypes. */
-#ifndef _MINIX_ANSI_H
-#include <minix/ansi.h>
-#endif
-
-_PROTOTYPE( int mount, (char *_spec, char *_name, int _mountflags,
-                                                char *type, char *args) );
-_PROTOTYPE( int umount, (const char *_name)                             );
-_PROTOTYPE( int umount2, (const char *_name, int flags)                 );
-
-#endif /* _MOUNT_H */