Clean up init-stdio implementations and move io.streams.null to basis

basis/io/backend/unix/unix.factor

@@ -173,10 +173,11 @@ M: stdin refill
         size-read-fd <fd> init-fd <input-port> >>size
         data-read-fd <fd> >>data ;
 
-M: unix (init-stdio)
+M: unix init-stdio
     <stdin> <input-port>
     1 <fd> <output-port>
-    2 <fd> <output-port> t ;
+    2 <fd> <output-port>
+    set-stdio ;
 
 ! mx io-task for embedding an fd-based mx inside another mx
 TUPLE: mx-port < port mx ;

basis/io/backend/windows/nt/nt.factor

@@ -1,9 +1,9 @@
-USING: alien alien.c-types arrays assocs combinators
-continuations destructors io io.backend io.ports io.timeouts
-io.backend.windows io.files.windows io.files.windows.nt io.files
-io.pathnames io.buffers io.streams.c libc kernel math namespaces
-sequences threads windows windows.errors windows.kernel32
-strings splitting ascii system accessors locals ;
+USING: alien alien.c-types arrays assocs combinators continuations
+destructors io io.backend io.ports io.timeouts io.backend.windows
+io.files.windows io.files.windows.nt io.files io.pathnames io.buffers
+io.streams.c io.streams.null libc kernel math namespaces sequences
+threads windows windows.errors windows.kernel32 strings splitting
+ascii system accessors locals ;
 QUALIFIED: windows.winsock
 IN: io.backend.windows.nt
 
@@ -140,7 +140,9 @@ M: winnt (wait-to-read) ( port -- )
 
 : console-app? ( -- ? ) GetConsoleWindow >boolean ;
 
-M: winnt (init-stdio)
-    console-app? [ init-c-stdio t ] [ f f f f ] if ;
+M: winnt init-stdio
+    console-app?
+    [ init-c-stdio ]
+    [ null-reader null-writer null-writer init-stdio ] if ;
 
 winnt set-io-backend

core/io/backend/backend.factor

@@ -1,7 +1,7 @@
 ! Copyright (C) 2007, 2009 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: init kernel system namespaces io io.encodings
-io.encodings.utf8 init assocs splitting alien io.streams.null ;
+io.encodings.utf8 init assocs splitting alien ;
 IN: io.backend
 
 SYMBOL: io-backend
@@ -12,22 +12,12 @@ io-backend [ c-io-backend ] initialize
 
 HOOK: init-io io-backend ( -- )
 
-HOOK: (init-stdio) io-backend ( -- stdin stdout stderr ? )
+HOOK: init-stdio io-backend ( -- )
 
-: set-stdio ( input-handle output-handle error-handle -- )
-    [ input-stream set-global ]
-    [ output-stream set-global ]
-    [ error-stream set-global ] tri* ;
-
-: init-stdio ( -- )
-    (init-stdio) [
-        [ utf8 <decoder> ]
-        [ utf8 <encoder> ]
-        [ utf8 <encoder> ] tri*
-    ] [
-        3drop
-        null-reader null-writer null-writer
-    ] if set-stdio ;
+: set-stdio ( input output error -- )
+    [ utf8 <decoder> input-stream set-global ]
+    [ utf8 <encoder> output-stream set-global ]
+    [ utf8 <encoder> error-stream set-global ] tri* ;
 
 HOOK: io-multiplex io-backend ( us -- )
 

core/io/streams/c/c.factor

@@ -60,12 +60,13 @@ M: c-io-backend init-io ;
 : stdout-handle ( -- alien ) 12 getenv ;
 : stderr-handle ( -- alien ) 61 getenv ;
 
-: init-c-stdio ( -- stdin stdout stderr )
+: init-c-stdio ( -- )
     stdin-handle <c-reader>
     stdout-handle <c-writer>
-    stderr-handle <c-writer> ;
+    stderr-handle <c-writer>
+    set-stdio ;
 
-M: c-io-backend (init-stdio) init-c-stdio t ;
+M: c-io-backend init-stdio init-c-stdio ;
 
 M: c-io-backend io-multiplex 60 60 * 1000 * 1000 * or (sleep) ;