Index: /trunk/source/level-1/linux-files.lisp
===================================================================
--- /trunk/source/level-1/linux-files.lisp	(revision 15396)
+++ /trunk/source/level-1/linux-files.lisp	(revision 15397)
@@ -1717,7 +1717,12 @@
     "Invoke an external program as an OS subprocess of lisp."
     (declare (ignore pty))
-    (unless (every #'(lambda (a) (typep a 'simple-string)) args)
+    (push program args)
+    (unless (do* ((args args (cdr args)))
+                 ((atom args)
+                  (or (typep args 'simple-string)
+                      (null args)))
+              (unless (typep (car args) 'simple-string)
+                (return)))
       (error "Program args must all be simple strings : ~s" args))
-    (push program args)
     (let* ((token (list 0))
            (in-fd nil)
@@ -1808,6 +1813,22 @@
         (monitor-external-process proc))))
 
-  (defun join-strings (strings)
-    (reduce (lambda (left right) (concatenate 'string left " " right)) strings))
+  (defun make-windows-command-line (strings)
+    (with-output-to-string (out)
+      (do* ((strings strings (cdr strings)))
+           ((atom strings)     
+            (if strings (write-string strings out)))
+        (let* ((string (car strings)))
+          (dotimes (i (length string))
+            (let* ((c (schar string i)))
+              (case c
+                ((#\space #\tab)
+                 (write-char #\" out)
+                 (write-char c out)
+                 (write-char #\" out))
+                (#\"
+                 (write-char #\\ out)
+                 (write-char #\" out))
+                (t (write-char c out)))))
+          (when strings (write-char #\space out))))))
 
   (defun create-windows-process (new-in new-out new-err cmdstring env)
@@ -1849,5 +1870,5 @@
   (defun exec-with-io-redirection (new-in new-out new-err args proc &optional env)
     (multiple-value-bind (win handle-to-process-or-error)
-        (create-windows-process new-in new-out new-err (join-strings args) env)
+        (create-windows-process new-in new-out new-err (make-windows-command-line args) env)
       (if win
         handle-to-process-or-error