--- a/libinterp/corefcn/oct-procbuf.cc	Thu Aug 11 08:16:52 2016 -0400
+++ b/libinterp/corefcn/oct-procbuf.cc	Thu Aug 11 12:33:26 2016 -0400
@@ -28,6 +28,18 @@
 
 #include <iostream>
 
+// FIXME: we would prefer to avoid including these directly in Octave
+// sources, but eliminating them is complicated by the mingling of
+// octave_procbuf_list and the calls to system library functions like
+// execl.
+
+#if defined (HAVE_UNISTD_H)
+#  if defined (HAVE_SYS_TYPES_H)
+#    include <sys/types.h>
+#  endif
+#  include <unistd.h>
+#endif
+
 #include "lo-mappers.h"
 #include "lo-utils.h"
 #include "oct-procbuf.h"
@@ -77,7 +89,7 @@
 
   return this;
 
-#elif defined (HAVE_SYS_WAIT_H)
+#elif defined (HAVE_UNISTD_H)
 
   int pipe_fds[2];
 
@@ -174,7 +186,7 @@
 
   return this;
 
-#elif defined (HAVE_SYS_WAIT_H)
+#elif defined (HAVE_UNISTD_H)
 
   if (f)
     {

--- a/libinterp/corefcn/toplev.cc	Thu Aug 11 08:16:52 2016 -0400
+++ b/libinterp/corefcn/toplev.cc	Thu Aug 11 12:33:26 2016 -0400
@@ -36,6 +36,7 @@
 #  include <windows.h>
 #endif
 
+#include "async-system-wrapper.h"
 #include "child-list.h"
 #include "lo-error.h"
 #include "oct-fftw.h"
@@ -246,41 +247,7 @@
 #endif
 
   if (type == et_async)
-    {
-      // FIXME: maybe this should go in sysdep.cc?
-#if defined (HAVE_FORK)
-      pid_t pid = fork ();
-
-      if (pid < 0)
-        error ("system: fork failed -- can't create child process");
-      else if (pid == 0)
-        {
-          // FIXME: should probably replace this call with something portable.
-          execl (SHELL_PATH, "sh", "-c", cmd_str.c_str (),
-                 static_cast<char *> (0));
-
-          panic_impossible ();
-        }
-      else
-        retval(0) = pid;
-#elif defined (OCTAVE_USE_WINDOWS_API)
-      STARTUPINFO si;
-      PROCESS_INFORMATION pi;
-      ZeroMemory (&si, sizeof (si));
-      ZeroMemory (&pi, sizeof (pi));
-      OCTAVE_LOCAL_BUFFER (char, xcmd_str, cmd_str.length ()+1);
-      strcpy (xcmd_str, cmd_str.c_str ());
-
-      if (! CreateProcess (0, xcmd_str, 0, 0, FALSE, 0, 0, 0, &si, &pi))
-        error ("system: CreateProcess failed -- can't create child process");
-
-      retval(0) = pi.dwProcessId;
-      CloseHandle (pi.hProcess);
-      CloseHandle (pi.hThread);
-#else
-      err_disabled_feature ("system", "asynchronous system calls");
-#endif
-    }
+    retval(0) = octave_async_system_wrapper (cmd_str.c_str ());
   else if (return_output)
     retval = run_command_and_return_output (cmd_str);
   else

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/liboctave/wrappers/async-system-wrapper.c	Thu Aug 11 12:33:26 2016 -0400
@@ -0,0 +1,87 @@
+/*
+
+Copyright (C) 2016 John W. Eaton
+
+This file is part of Octave.
+
+Octave is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 3 of the License, or (at your
+option) any later version.
+
+Octave is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with Octave; see the file COPYING.  If not, see
+<http://www.gnu.org/licenses/>.
+
+*/
+
+// areadlink is provided by gnulib.  We don't include gnulib headers
+// directly in Octave's C++ source files to avoid problems that may be
+// caused by the way that gnulib overrides standard library functions.
+
+#if defined (HAVE_CONFIG_H)
+#  include "config.h"
+#endif
+
+#if defined (__WIN32__) && ! defined (__CYGWIN__)
+#  include <stdlib.h>
+#  include <string.h>
+#  define WIN32_LEAN_AND_MEAN 1
+#  include <windows.h>
+#else
+#  include <sys/types.h>
+#  include <unistd.h>
+#endif
+
+#include "async-system-wrapper.h"
+
+pid_t
+octave_async_system_wrapper (const char *cmd)
+{
+  int retval = -1;
+
+  if (! cmd)
+    return retval;
+
+#if defined (OCTAVE_USE_WINDOWS_API)
+
+  STARTUPINFO si;
+  PROCESS_INFORMATION pi;
+
+  ZeroMemory (&si, sizeof (si));
+  ZeroMemory (&pi, sizeof (pi));
+
+  char *xcmd = (char *) malloc (strlen (cmd) + 1);
+
+  strcpy (xcmd, cmd);
+
+  if (! CreateProcess (0, xcmd, 0, 0, FALSE, 0, 0, 0, &si, &pi))
+    retval = -1;
+  else
+    {
+      retval = pi.dwProcessId;
+
+      CloseHandle (pi.hProcess);
+      CloseHandle (pi.hThread);
+    }
+
+  free (xcmd);
+
+#else
+
+  pid_t pid = fork ();
+
+  if (pid == 0)
+    execl (SHELL_PATH, "sh", "-c", cmd, (char *) (0));
+  else
+    retval = pid;
+
+#endif
+
+  return retval;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/liboctave/wrappers/async-system-wrapper.h	Thu Aug 11 12:33:26 2016 -0400
@@ -0,0 +1,38 @@
+/*
+
+Copyright (C) 2016 John W. Eaton
+
+This file is part of Octave.
+
+Octave is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 3 of the License, or (at your
+option) any later version.
+
+Octave is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with Octave; see the file COPYING.  If not, see
+<http://www.gnu.org/licenses/>.
+
+*/
+
+#if ! defined (octave_async_system_wrapper_h)
+#define octave_async_system_wrapper_h 1
+
+#include <sys/types.h>
+
+#if defined __cplusplus
+extern "C" {
+#endif
+
+extern pid_t octave_async_system_wrapper (const char *cmd);
+
+#if defined __cplusplus
+}
+#endif
+
+#endif

--- a/liboctave/wrappers/module.mk	Thu Aug 11 08:16:52 2016 -0400
+++ b/liboctave/wrappers/module.mk	Thu Aug 11 12:33:26 2016 -0400
@@ -1,5 +1,6 @@
 NOINSTALL_WRAPPERS_INC = \
   liboctave/wrappers/areadlink-wrapper.h \
+  liboctave/wrappers/async-system-wrapper.h \
   liboctave/wrappers/base64-wrappers.h \
   liboctave/wrappers/canonicalize-file-name-wrapper.h \
   liboctave/wrappers/dirent-wrappers.h \
@@ -34,6 +35,7 @@
 
 WRAPPERS_SRC = \
   liboctave/wrappers/areadlink-wrapper.c \
+  liboctave/wrappers/async-system-wrapper.c \
   liboctave/wrappers/base64-wrappers.c \
   liboctave/wrappers/canonicalize-file-name-wrapper.c \
   liboctave/wrappers/dirent-wrappers.c \