--- guile-1.9.15/module/system/base/compile.scm~	2011-02-15 10:54:38.483090146 +0100
+++ guile-1.9.15/module/system/base/compile.scm	2011-03-03 09:15:24.742333809 +0100
@@ -51,7 +51,7 @@
 ;; (put 'call-with-output-file/atomic 'scheme-indent-function 1)
 (define* (call-with-output-file/atomic filename proc #:optional reference)
   (let* ((template (string-append filename ".XXXXXX"))
-         (tmp (mkstemp! template)))
+         (tmp (mkstemp! template "w+b")))
     (call-once
      (lambda ()
        (with-throw-handler #t
--- guile-1.9.15/libguile/posix.h~	2010-12-14 19:15:17.000000000 +0100
+++ guile-1.9.15/libguile/posix.h	2011-03-03 09:21:46.058955734 +0100
@@ -67,7 +67,7 @@
 SCM_API SCM scm_uname (void);
 SCM_API SCM scm_environ (SCM env);
 SCM_API SCM scm_tmpnam (void);
-SCM_API SCM scm_mkstemp (SCM tmpl);
+SCM_API SCM scm_mkstemp (SCM tmpl, SCM mode);
 SCM_API SCM scm_tmpfile (void);
 SCM_API SCM scm_open_pipe (SCM pipestr, SCM modes);
 SCM_API SCM scm_close_pipe (SCM port);
--- guile-1.9.15/libguile/posix.c~	2011-01-29 21:36:58.000000000 +0100
+++ guile-1.9.15/libguile/posix.c	2011-03-03 09:14:46.745199721 +0100
@@ -1329,8 +1329,8 @@
 extern int mkstemp (char *);
 #endif
 
-SCM_DEFINE (scm_mkstemp, "mkstemp!", 1, 0, 0,
-	    (SCM tmpl),
+SCM_DEFINE (scm_mkstemp, "mkstemp!", 1, 1, 0,
+	    (SCM tmpl, SCM mode),
 	    "Create a new unique file in the file system and return a new\n"
 	    "buffered port open for reading and writing to the file.\n"
 	    "\n"
@@ -1338,6 +1338,8 @@
 	    "created: it must end with @samp{XXXXXX} and those @samp{X}s\n"
 	    "will be changed in the string to return the name of the file.\n"
 	    "(@code{port-filename} on the port also gives the name.)\n"
+	    "The optional @var{mode}, if given, is a string specifying the\n"
+	    "open mode of the file, e.g. w+b\n"
 	    "\n"
 	    "POSIX doesn't specify the permissions mode of the file, on GNU\n"
 	    "and most systems it's @code{#o600}.  An application can use\n"
@@ -1354,7 +1356,12 @@
 {
   char *c_tmpl;
   int rv;
-  
+  SCM port;
+  char *c_mode = "w+";
+
+  if (!SCM_UNBNDP (mode))
+    c_mode = scm_to_locale_string (mode);
+
   scm_dynwind_begin (0);
 
   c_tmpl = scm_to_locale_string (tmpl);
@@ -1369,7 +1376,10 @@
 			tmpl, SCM_INUM0);
 
   scm_dynwind_end ();
-  return scm_fdes_to_port (rv, "w+", tmpl);
+  port = scm_fdes_to_port (rv, c_mode, tmpl);
+  if (!SCM_UNBNDP (mode))
+    free (c_mode);
+  return port;
 }
 #undef FUNC_NAME