--- gdb/serial.c	(/mirrors/gdb_mainline)	(revision 3222)
+++ gdb/serial.c	(/patches/gdb/remote_stderr/gdb_mainline)	(revision 3222)
@@ -211,6 +211,7 @@ serial_open (const char *name)
 
   scb->bufcnt = 0;
   scb->bufp = scb->buf;
+  scb->error_fd = -1;
 
   if (scb->ops->open (scb, open_name))
     {
--- gdb/serial.h	(/mirrors/gdb_mainline)	(revision 3222)
+++ gdb/serial.h	(/patches/gdb/remote_stderr/gdb_mainline)	(revision 3222)
@@ -191,6 +191,12 @@ extern int serial_debug_p (struct serial
 struct serial
   {
     int fd;			/* File descriptor */
+    int error_fd;               /* File descriptor for a separate
+				   error stream that should be
+				   immediately forwarded to gdb_stderr.
+				   This may be -1.  
+				   If != -1, this descriptor should
+				   be non-blocking.  */
     struct serial_ops *ops;	/* Function vector */
     void *state;       		/* Local context info for open FD */
     serial_ttystate ttystate;	/* Not used (yet) */
--- gdb/ser-pipe.c	(/mirrors/gdb_mainline)	(revision 3222)
+++ gdb/ser-pipe.c	(/patches/gdb/remote_stderr/gdb_mainline)	(revision 3222)
@@ -62,9 +62,12 @@ pipe_open (struct serial *scb, const cha
    * published in UNIX Review, Vol. 6, No. 8.
    */
   int pdes[2];
+  int err_pdes[2];
   int pid;
   if (socketpair (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
     return -1;
+  if (socketpair (AF_UNIX, SOCK_STREAM, 0, err_pdes) < 0)
+    return -1;
 
   /* Create the child process to run the command in.  Note that the
      apparent call to vfork() below *might* actually be a call to
@@ -77,9 +80,18 @@ pipe_open (struct serial *scb, const cha
     {
       close (pdes[0]);
       close (pdes[1]);
+      close (err_pdes[0]);
+      close (err_pdes[1]);
       return -1;
     }
 
+  if (fcntl (err_pdes[0], F_SETFL, O_NONBLOCK) == -1)
+    {
+      close (err_pdes[0]);
+      close (err_pdes[1]);
+      err_pdes[0] = err_pdes[1] = -1;
+    }
+
   /* Child. */
   if (pid == 0)
     {
@@ -91,6 +103,13 @@ pipe_open (struct serial *scb, const cha
 	  close (pdes[1]);
 	}
       dup2 (STDOUT_FILENO, STDIN_FILENO);
+
+      if (err_pdes[0] != -1)
+	{
+	  close (err_pdes[0]);
+	  dup2 (err_pdes[1], STDERR_FILENO);
+	  close (err_pdes[1]);
+	}
 #if 0
       /* close any stray FD's - FIXME - how? */
       /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
@@ -109,6 +128,7 @@ pipe_open (struct serial *scb, const cha
   state = XMALLOC (struct pipe_state);
   state->pid = pid;
   scb->fd = pdes[0];
+  scb->error_fd = err_pdes[0];
   scb->state = state;
 
   /* If we don't do this, GDB simply exits when the remote side dies.  */
--- gdb/ser-base.c	(/mirrors/gdb_mainline)	(revision 3222)
+++ gdb/ser-base.c	(/patches/gdb/remote_stderr/gdb_mainline)	(revision 3222)
@@ -314,6 +314,33 @@ generic_readchar (struct serial *scb, in
 		  int (do_readchar) (struct serial *scb, int timeout))
 {
   int ch;
+
+  /* Read any error output we might have.  */
+  if (scb->error_fd != -1)
+    {
+      ssize_t s;
+      char buf[81];
+      while ((s = read (scb->error_fd, &buf, 80)) > 0)
+	{
+	  char *current;
+	  char *newline;
+	  /* In theory, embedded newlines are not a problem.
+	     But for MI, we want each output line to have just
+	     one newline for legibility.  So output things
+	     in newline chunks.  */
+	  buf[s] = '\0';
+	  current = buf;
+	  while ((newline = strstr (current, "\n")) != NULL)
+	    {
+	      *newline = '\0';
+	      fputs_unfiltered (current, gdb_stderr);
+	      fputs_unfiltered ("\n", gdb_stderr);
+	      current = newline + 1;
+	    }
+	  fputs_unfiltered (current, gdb_stderr);
+	}
+    }
+
   if (scb->bufcnt > 0)
     {
       ch = *scb->bufp;