#if defined(HAVE_SIGSET) && !defined(signal)
# define signal sigset
#endif
#if defined(HAVE_SYS_IOCTL_H) && !defined(SUN_SYSTEM)
# include <sys/ioctl.h>
#endif
#ifndef USE_SYSTEM // use fork/exec to start the shell
# if defined(HAVE_SYS_WAIT_H) || defined(HAVE_UNION_WAIT)
# include <sys/wait.h>
# endif
# ifndef WEXITSTATUS
# ifdef HAVE_UNION_WAIT
# define WEXITSTATUS(stat_val) ((stat_val).w_T.w_Retcode)
# else
# define WEXITSTATUS(stat_val) (((stat_val) >> 8) & 0377)
# endif
# endif
# ifndef WIFEXITED
# ifdef HAVE_UNION_WAIT
# define WIFEXITED(stat_val) ((stat_val).w_T.w_Termsig == 0)
# else
# define WIFEXITED(stat_val) (((stat_val) & 255) == 0)
# endif
# endif
#endif // !USE_SYSTEM
#ifdef HAVE_STROPTS_H
# ifdef sinix
# define buf_T __system_buf_t__
# endif
# include <stropts.h>
# ifdef sinix
# undef buf_T
# endif
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#ifdef HAVE_SYS_STREAM_H
# include <sys/stream.h>
#endif
#ifdef HAVE_SYS_UTSNAME_H
# include <sys/utsname.h>
#endif
#ifdef HAVE_SYS_SYSTEMINFO_H
# ifndef SYS_NMLN
# define SYS_NMLN 32
# endif
# include <sys/systeminfo.h> // for sysinfo
#endif
#if defined(HAVE_TERMIOS_H) && !defined(apollo)
# include <termios.h>
#else
# ifdef HAVE_TERMIO_H
# include <termio.h>
# else
# ifdef HAVE_SGTTY_H
# include <sgtty.h>
# endif
# endif
#endif
#ifdef HAVE_SYS_PTEM_H
# include <sys/ptem.h> // must be after termios.h for Sinix
# ifndef _IO_PTEM_H // For UnixWare that should check for _IO_PT_PTEM_H
# define _IO_PTEM_H
# endif
#endif
#if defined(HAVE_DLFCN_H) && defined(USE_DLOPEN)
# if defined(__MVS__) && !defined (__SUSV3)
# define __SUSV3
# endif
# include <dlfcn.h>
#else
# if defined(HAVE_DL_H) && defined(HAVE_SHL_LOAD)
# include <dl.h>
# endif
#endif