MCCS coding for UNIX-GETENV, fix MTOUTF8STRING (#2474)

* MCCS translations for strings passed to/from UNIX-GETENV and other system interfaces.
* INTERPRET.REM.CM assumes system external format is UTF-8.  ISO8859/1 external format is defined in MCCS as a dummy for UTF-8 until UNICODE is loaded
* Add string translation interface to EXTERNALFORMAT datatype, 
* Set the external format of the default reader environment to *DEFAULT-EXTERNALFORMAT* = :MCCS
* Add external format :THROUGH16 for 16 bit codes, used by linebuffer

library/UNIXPRINT

@@ -1,12 +1,12 @@
 (DEFINE-FILE-INFO PACKAGE "INTERLISP" READTABLE "INTERLISP" BASE 10)
 
-
(FILECREATED "25-Jan-2026 11:09:09" {WMEDLEY}<library>UNIXPRINT.;15
 11553  
+
(FILECREATED " 5-Feb-2026 18:37:09" {WMEDLEY}<library>UNIXPRINT.;17
 11663  
 
       :EDIT-BY rmk
 
-      :CHANGES-TO (FNS UnixPrint)
+      :CHANGES-TO (FNS UnixShellQuote)
 
-      :PREVIOUS-DATE "18-Jan-2026 08:44:40" {WMEDLEY}<library>UNIXPRINT.;14)
+      :PREVIOUS-DATE "25-Jan-2026 11:09:09" {WMEDLEY}<library>UNIXPRINT.;15)
 
 
 (PRETTYCOMPRINT UNIXPRINTCOMS)
@@ -130,7 +130,8 @@
 
 (UnixShellQuote

   [LAMBDA (STRING)
-    (DECLARE
 (LOCALVARS . T))
                                (* ; "Edited 18-Jan-2026 08:34 by rmk")


+    (DECLARE
 (LOCALVARS . T))
                                (* ; "Edited  5-Feb-2026 18:37 by rmk")


+                                                             (* ; "Edited 18-Jan-2026 08:34 by rmk")


                                                              (* ; "Edited 19-Apr-89 21:14 by TAL")

     (LET* ((X (CHCON STRING))
            (CT X)
@@ -155,9 +156,9 @@
                                                       (CHARCODE SPACE))
                                                      (T C))
                                                   (SETQ CT (CDR CT]
-          (MTOUTF8STRING (COND
-                            (FLG (CONCATCODES X))
-                            (T STRING])
+          (MTOSYSSTRING (CL:IF FLG
+                            (CONCATCODES X)
+                            STRING)])
 
 (UnixTempFile

   [LAMBDA (Prefix DontOpen)
                                  (* ; "Edited 28-Apr-93 13:49 by rmk:")


@@ -251,6 +252,6 @@
 (ADDTOVAR LAMA
 )
 )
 (DECLARE%: DONTCOPY
-  (FILEMAP (NIL (1046 10887 (UnixPrint 1056 . 6392) (UnixShellQuote 6394 . 7977) (UnixTempFile 7979 . 
-9202) (UnixPrintCommand 9204 . 10885)))))
+  (FILEMAP (NIL (1051 10997 (UnixPrint 1061 . 6397) (UnixShellQuote 6399 . 8087) (UnixTempFile 8089 . 
+9312) (UnixPrintCommand 9314 . 10995)))))
 STOP