(Fcall_process): Handle t or nil as STDERR_FILE.

1 files changed, 10 insertions, 2 deletions

diff --git a/src/callproc.c b/src/callproc.c
index 4d84c98edb7..3e79b6064f5 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -245,8 +245,16 @@ If you quit, the process is killed with SIGINT, or SIGKILL if you quit again.")
       if (CONSP (buffer))
         {
           if (CONSP (XCONS (buffer)->cdr))
-            error_file = Fexpand_file_name (XCONS (XCONS (buffer)->cdr)->car,
-                                            Qnil);
+            {
+              Lisp_Object file_for_stderr;
+              stderr_file = XCONS (XCONS (buffer)->cdr)->car;
+
+              if (NILP (stderr_file) || EQ (Qt, stderr_file))
+                error_file = stderr_file;
+              else
+                error_file = Fexpand_file_name (stderr_file, Qnil);
+            }
+
           buffer = XCONS (buffer)->car;
         }