dnl Process this file with autoconf to produce a configure script.
dnl
dnl $Id$ GNU
dnl
dnl Many thanks to David MacKenzie for writing autoconf and
dnl providing a sample configure.in file for screen.
dnl
AC_REVISION($Revision$)dnl
AC_INIT(screen.c)
AC_CONFIG_HEADER(config.h)
AC_PREREQ(2.60)

dnl
dnl Define some useful macros
dnl
AC_DEFUN([AC_PROGRAM_SOURCE],
[AC_REQUIRE([AC_PROG_CPP])AC_PROVIDE([$0])cat > conftest.c <<EOF
#include "confdefs.h"
[$1]
_CUT_HERE_
[$2]
EOF
eval "$ac_cpp conftest.c 2>&5 | sed -e '1,/_CUT_HERE_/d' -e 's/ //g' > conftest.out"
. ./conftest.out
rm -f conftest*
])dnl
dnl
define(AC_NOTE,
[echo "$1" 1>&AC_FD_MSG
])dnl

dnl
dnl Extract version from patchlevel.h
dnl
rev=`sed < ${srcdir}/patchlevel.h -n -e '/#define REV/s/#define REV  *//p'`
vers=`sed < ${srcdir}/patchlevel.h -n -e '/#define VERS/s/#define VERS  *//p'`
pat=`sed < ${srcdir}/patchlevel.h -n -e '/#define PATCHLEVEL/s/#define PATCHLEVEL  *//p'`
VERSION="$rev.$vers.$pat"
AC_NOTE(this is screen version $VERSION)
AC_SUBST(VERSION)
AC_PREFIX_PROGRAM(screen)
AC_PREFIX_PROGRAM(gzip)

old_CFLAGS="$CFLAGS"
AC_PROG_CC
AC_PROG_CPP
AC_PROG_GCC_TRADITIONAL
AC_ISC_POSIX
AC_USE_SYSTEM_EXTENSIONS

AC_PROG_AWK

AC_PROG_INSTALL

if test -f etc/toolcheck; then
AC_CHECKING(for buggy tools)
sh etc/toolcheck 1>&AC_FD_MSG
fi



dnl SOCKDIR
AC_MSG_CHECKING(if a system-wide socket dir should be used) 
AC_ARG_ENABLE(socket-dir,
    [  --disable-socket-dir    disable system wide socket-dir and use ~/.screen instead],
    [
	AC_MSG_RESULT(no.  ~/.screen will be used instead.)
    ],
    [
	AC_MSG_RESULT(yes)
	AC_MSG_CHECKING(for the socket dir)
	SOCKDIR="(eff_uid ? \"/tmp/uscreens\" : \"/tmp/screens\")"
	AC_ARG_WITH(socket-dir, [  --with-socket-dir=path  where to put the per-user sockets], [ 
	  case "${withval}" in
	    *\"*) SOCKDIR="${withval}" ;;
	    *) SOCKDIR="\"${withval}\"" ;;
	  esac
        ])
	AC_MSG_RESULT(${SOCKDIR})
	AC_DEFINE_UNQUOTED(SOCKDIR, $SOCKDIR)
    ]
)


dnl
dnl    ****  special unix variants  ****
dnl
if test "$cross_compiling" = no && test -n "$ISC" ; then
  AC_DEFINE(ISC) LIBS="$LIBS -linet"
fi

dnl AC_CHECKING(for OSF1)
dnl if test -f /bin/uname ; then
dnl if test `/bin/uname` = OSF1 || test -f /osf_boot; then
dnl AC_DEFINE(OSF1)	# this disables MIPS again....
dnl fi
dnl fi

if test "$cross_compiling" = no && test -f /sysV68 ; then
AC_DEFINE(sysV68)
fi

if test "$cross_compiling" = no ; then
AC_CHECKING(for MIPS)
if test -f /lib/libmld.a || test -f /usr/lib/libmld.a || test -f /usr/lib/cmplrs/cc/libmld.a; then
oldlibs="$LIBS"
test -f /bin/mx || LIBS="$LIBS -lmld" # for nlist. But not on alpha.
dnl djm@eng.umd.edu: "... for one thing, it doubles the size of the executable"
AC_CHECKING(mld library)
AC_TRY_LINK(,,,LIBS="$oldlibs")
dnl
dnl
if test -r /dev/ptc; then
AC_DEFINE(MIPS)
AC_CHECKING(wait3)
AC_TRY_LINK(,[wait3();], ,
AC_CHECKING(wait2)
AC_TRY_LINK(,[wait2();],
dnl John Rouillard (rouilj@sni-usa.com):
dnl need -I/usr/include/bsd in RISCOS otherwise sockets are broken, no
dnl job control etc.
dnl Detect RISCOS if wait2 is present, but not wait3.
AC_DEFINE(USE_WAIT2) LIBS="$LIBS -lbsd" ; CC="$CC -I/usr/include/bsd"
))
fi
fi
fi


AC_CHECKING(for Ultrix)
AC_EGREP_CPP(YES_IS_DEFINED,
[#if defined(ultrix) || defined(__ultrix)
   YES_IS_DEFINED;
#endif
], ULTRIX=1)

if test "$cross_compiling" = no && test -f /usr/lib/libpyr.a ; then
oldlibs="$LIBS"
LIBS="$LIBS -lpyr"
AC_CHECKING(Pyramid OSX)
AC_TRY_LINK(,[open_controlling_pty("")], AC_DEFINE(OSX), LIBS="$oldlibs")
fi

dnl ghazi@caip.rutgers.edu (Kaveh R. Ghazi):
dnl BBN butterfly is not POSIX, but a MACH BSD system.
dnl Do not define POSIX and TERMIO.
AC_CHECKING(for butterfly)
AC_EGREP_CPP(YES_IS_DEFINED,
[#if defined(butterfly)
  YES_IS_DEFINED;
#endif
], butterfly=1)

if test -z "$butterfly"; then
if test -n "$ULTRIX"; then
  test -z "$GCC" && CC="$CC -YBSD"
fi
AC_CHECKING(for POSIX.1)
AC_EGREP_CPP(YES_IS_DEFINED,
[#include <sys/types.h>
#include <unistd.h>
main () {
#ifdef _POSIX_VERSION
  YES_IS_DEFINED;
#endif
], AC_NOTE(- you have a POSIX system) AC_DEFINE(POSIX) posix=1)
fi

AC_CHECKING(for System V)
AC_TRY_COMPILE(
[#include <sys/types.h>
#include <signal.h>
#include <fcntl.h>], [int x = SIGCHLD | FNDELAY;], , AC_DEFINE(SYSV))

AC_CHECKING(for sequent/ptx)
AC_EGREP_CPP(YES_IS_DEFINED,
[#ifdef _SEQUENT_
  YES_IS_DEFINED;
#endif
], LIBS="$LIBS -lsocket -linet";seqptx=1)

AC_CHECKING(SVR4)
AC_EGREP_CPP(yes,
[main () {
#if defined(SVR4) || defined(__SVR4)
  yes;
#endif
], AC_NOTE(- you have a SVR4 system) AC_DEFINE(SVR4) svr4=1)
if test -n "$svr4" ; then
oldlibs="$LIBS"
LIBS="$LIBS -lelf"
AC_CHECKING(SVR4)
AC_TRY_LINK([#include <utmpx.h>
],,
[AC_CHECK_HEADER(dwarf.h, AC_DEFINE(BUGGYGETLOGIN),
[AC_CHECK_HEADER(elf.h, AC_DEFINE(BUGGYGETLOGIN))])]
,LIBS="$oldlibs")
fi

AC_CHECK_HEADERS([stropts.h string.h strings.h])

AC_CHECKING(for Solaris 2.x)
AC_EGREP_CPP(YES_IS_DEFINED,
[#if defined(SVR4) && defined(sun)
  YES_IS_DEFINED;
#endif
], LIBS="$LIBS -lsocket -lnsl -lkstat")

dnl
dnl    ****  typedefs ****
dnl
dnl (currently not used)
dnl
dnl AC_CHECKING(for pid_t)
dnl AC_EGREP_CPP(pid_t,[#include <sys/types.h>
dnl ],AC_DEFINE(PID_T_DEFINED))
dnl
dnl AC_CHECKING(for sig_t)
dnl AC_EGREP_CPP(sig_t,[#include <sys/types.h>
dnl #include <signal.h>
dnl ],AC_DEFINE(SIG_T_DEFINED))
dnl
dnl AC_CHECKING(for uid_t)
dnl AC_EGREP_CPP(uid_t,[#include <sys/types.h>
dnl ],AC_DEFINE(UID_T_DEFINED))
dnl

dnl
dnl   ****     Job control     ****
dnl

AC_CHECKING(BSD job jontrol)
AC_TRY_LINK(
[#include <sys/types.h>
#include <sys/ioctl.h>
], [
#ifdef POSIX
tcsetpgrp(0, 0);
#else
int x = TIOCSPGRP;
#ifdef SYSV
setpgrp();
#else
int y = TIOCNOTTY;
#endif
#endif
], AC_NOTE(- you have jobcontrol) AC_DEFINE(BSDJOBS), AC_NOTE(- you don't have jobcontrol))

dnl
dnl    ****  setresuid(), setreuid(), seteuid()  ****
dnl
AC_CHECKING(setresuid)
AC_TRY_LINK(,[
setresuid(0, 0, 0);
], AC_DEFINE(HAVE_SETRESUID))
AC_CHECKING(setreuid)
AC_TRY_LINK(,[
setreuid(0, 0);
], AC_DEFINE(HAVE_SETREUID))
dnl
dnl seteuid() check:
dnl   linux seteuid was broken before V1.1.11
dnl   NeXT, AUX, ISC, and ultrix are still broken (no saved uid support)
dnl   Solaris seteuid doesn't change the saved uid, bad for
dnl     multiuser screen sessions
AC_CHECKING(seteuid)
AC_TRY_LINK(,[
#if defined(linux) || defined(NeXT) || defined(_AUX_SOURCE) || defined(AUX) || defined(ultrix) || (defined(sun) && defined(SVR4)) || defined(ISC) || defined(sony_news)
seteuid_is_broken(0);
#else
seteuid(0);
#endif
], AC_DEFINE(HAVE_SETEUID))

dnl execvpe
AC_CHECKING(execvpe)
AC_TRY_LINK(,[
    execvpe(0, 0, 0);
], AC_DEFINE(HAVE_EXECVPE)
CFLAGS="$CFLAGS -D_GNU_SOURCE")

dnl
dnl    ****  select()  ****
dnl

AC_CHECKING(select)
AC_TRY_LINK(,[select(0, 0, 0, 0, 0);],, 
LIBS="$LIBS -lnet -lnsl"
AC_CHECKING(select with $LIBS)
AC_TRY_LINK(,[select(0, 0, 0, 0, 0);],, 
AC_MSG_ERROR(!!! no select - no screen))
)
dnl
dnl    ****  FIFO tests  ****
dnl

AC_CHECKING(fifos)
AC_TRY_RUN([
/* For select - According to POSIX 1003.1-2001 */
#include <sys/select.h>

/* For select - According to earlier standards */
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

#include <sys/stat.h>
#include <fcntl.h>

#ifndef O_NONBLOCK
#define O_NONBLOCK O_NDELAY
#endif
#ifndef S_IFIFO
#define S_IFIFO 0010000
#endif

char *fin = "/tmp/conftest$$";

main()
{
  struct stat stb;
  fd_set f;

  (void)alarm(5);
  unlink(fin);
#ifdef POSIX
  if (mkfifo(fin, 0777))
#else
  if (mknod(fin, S_IFIFO|0777, 0))
#endif
    exit(1);
  if (stat(fin, &stb) || (stb.st_mode & S_IFIFO) != S_IFIFO)
    exit(1);
  close(0);
#ifdef __386BSD__
  /*
   * The next test fails under 386BSD, but screen works using fifos.
   * Fifos in O_RDWR mode are only used for the BROKEN_PIPE case and for
   * the select() configuration test.
   */
  exit(0);
#endif
  if (open(fin, O_RDONLY | O_NONBLOCK))
    exit(1);
  if (fork() == 0)
    {
      close(0);
      if (open(fin, O_WRONLY | O_NONBLOCK))
	exit(1);
      close(0);
      if (open(fin, O_WRONLY | O_NONBLOCK))
	exit(1);
      if (write(0, "TEST", 4) == -1)
	exit(1);
      exit(0);
    }
  FD_SET(0, &f);
  if (select(1, &f, 0, 0, 0) == -1)
    exit(1);
  exit(0);
}
], AC_NOTE(- your fifos are usable) fifo=1,
AC_NOTE(- your fifos are not usable),
AC_NOTE(- skipping check because we are cross compiling; assuming fifos are usable) fifo=1)
rm -f /tmp/conftest*

if test -n "$fifo"; then
AC_CHECKING(for broken fifo implementation)
AC_TRY_RUN([
/* For select - According to POSIX 1003.1-2001 */
#include <sys/select.h>

/* For select - According to earlier standards */
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

#include <sys/stat.h>
#include <fcntl.h>

#ifndef O_NONBLOCK
#define O_NONBLOCK O_NDELAY
#endif
#ifndef S_IFIFO
#define S_IFIFO 0010000
#endif

char *fin = "/tmp/conftest$$";

main()
{
  struct timeval tv;
  fd_set f;

#ifdef POSIX
  if (mkfifo(fin, 0600))
#else
  if (mknod(fin, S_IFIFO|0600, 0))
#endif
    exit(1);
  close(0);
  if (open(fin, O_RDONLY|O_NONBLOCK))
    exit(1);
  FD_SET(0, &f);
  tv.tv_sec = 1;
  tv.tv_usec = 0;
  if (select(1, &f, 0, 0, &tv))
    exit(1);
  exit(0);
}
], AC_NOTE(- your implementation is ok), 
AC_NOTE(- you have a broken implementation) AC_DEFINE(BROKEN_PIPE) fifobr=1,
AC_NOTE(- skipping check because we are cross compiling; assuming fifo implementation is ok))
rm -f /tmp/conftest*
fi

dnl
dnl    ****  SOCKET tests  ****
dnl 
dnl 	may need  	LIBS="$LIBS -lsocket" 	here
dnl

AC_CHECKING(sockets)
AC_TRY_RUN([
/* For select - According to POSIX 1003.1-2001 */
#include <sys/select.h>

/* For select - According to earlier standards */
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

#include <sys/stat.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/un.h>

char *son = "/tmp/conftest$$";

main()
{
  int s1, s2, l;
  struct sockaddr_un a;
  fd_set f;

  (void)alarm(5);
  if ((s1 = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
    exit(1);
  a.sun_family = AF_UNIX;
  strcpy(a.sun_path, son);
  (void) unlink(son);
  if (bind(s1, (struct sockaddr *) &a, strlen(son)+2) == -1)
    exit(1);
  if (listen(s1, 2))
    exit(1);
  if (fork() == 0)
    {
      if ((s2 = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
	kill(getppid(), 3);
      (void)connect(s2, (struct sockaddr *)&a, strlen(son) + 2);
      if (write(s2, "HELLO", 5) == -1)
	kill(getppid(), 3);
      exit(0);
    }
  l = sizeof(a);
  close(0);
  if (accept(s1, &a, &l))
    exit(1);
  FD_SET(0, &f);
  if (select(1, &f, 0, 0, 0) == -1)
    exit(1);
  exit(0);
}
], AC_NOTE(- your sockets are usable) sock=1,
AC_NOTE(- your sockets are not usable),
AC_NOTE(- skipping check because we are cross compiling; assuming sockets are usable) sock=1)
rm -f /tmp/conftest*

if test -n "$sock"; then
AC_CHECKING(socket implementation)
AC_TRY_RUN([
/* For select - According to POSIX 1003.1-2001 */
#include <sys/select.h>

/* For select - According to earlier standards */
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>

char *son = "/tmp/conftest$$";

main()
{
  int s;
  struct stat stb;
  struct sockaddr_un a;
  if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
    exit(0);
  a.sun_family = AF_UNIX;
  strcpy(a.sun_path, son);
  (void) unlink(son);
  if (bind(s, (struct sockaddr *) &a, strlen(son)+2) == -1)
    exit(0);
  if (stat(son, &stb))
    exit(1);
  close(s);
  exit(0);
}
],AC_NOTE(- you are normal),
AC_NOTE(- unix domain sockets are not kept in the filesystem)
AC_DEFINE(SOCK_NOT_IN_FS) socknofs=1,
AC_NOTE(- skipping check because we are cross compiling; assuming sockets are normal))
rm -f /tmp/conftest*
fi


dnl
dnl    ****  choose sockets or fifos  ****
dnl
dnl    ****  check the select implementation ****
dnl

AC_TRY_RUN([
/* For select - According to POSIX 1003.1-2001 */
#include <sys/select.h>

/* For select - According to earlier standards */
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

#include <sys/stat.h>
#include <fcntl.h>

char *nam = "/tmp/conftest$$";

#ifdef NAMEDPIPE

#ifndef O_NONBLOCK
#define O_NONBLOCK O_NDELAY
#endif
#ifndef S_IFIFO
#define S_IFIFO 0010000
#endif

main()
{
  fd_set f;

#ifdef __FreeBSD__
/* From Andrew A. Chernov (ache@astral.msk.su):
 * opening RDWR fifo fails in BSD 4.4, but select return values are
 * right.
 */
  exit(0);
#endif
  (void)alarm(5);
#ifdef POSIX
  if (mkfifo(nam, 0777))
#else
  if (mknod(nam, S_IFIFO|0777, 0))
#endif
    exit(1);
  close(0);
  if (open(nam, O_RDWR | O_NONBLOCK))
    exit(1);
  if (write(0, "TEST", 4) == -1)
    exit(1);

#else

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>

main()
{
  int s1, s2, l;
  struct sockaddr_un a;
  fd_set f;

  (void)alarm(5);
  if ((s1 = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
    exit(1);
  a.sun_family = AF_UNIX;
  strcpy(a.sun_path, nam);
  (void) unlink(nam);
  if (bind(s1, (struct sockaddr *) &a, strlen(nam)+2) == -1)
    exit(1);
  if (listen(s1, 2))
    exit(1);
  if (fork() == 0)
    {
      if ((s2 = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
	kill(getppid(), 3);
      (void)connect(s2, (struct sockaddr *)&a, strlen(nam) + 2);
      if (write(s2, "HELLO", 5) == -1)
	kill(getppid(), 3);
      exit(0);
    }
  l = sizeof(a);
  close(0);
  if (accept(s1, (struct sockaddr *)&a, &l))
    exit(1);
#endif


  FD_SET(0, &f);
  if (select(1, &f, 0, 0, 0) == -1)
    exit(1);
  if (select(1, &f, &f, 0, 0) != 2)
    exit(1);
  exit(0);
}
],AC_NOTE(- select is ok),
AC_NOTE(- select can't count) AC_DEFINE(SELECT_BROKEN),
AC_NOTE(- skipping check because we are cross compiling; assuming select is ok))

dnl
dnl    ****  termcap or terminfo  ****
dnl
AC_CHECKING(for tgetent)
AC_TRY_LINK(,tgetent((char *)0, (char *)0);,,
olibs="$LIBS"
LIBS="-lcurses $olibs"
AC_CHECKING(libcurses)
AC_TRY_LINK(,[
#ifdef __hpux
__sorry_hpux_libcurses_is_totally_broken_in_10_10();
#else
tgetent((char *)0, (char *)0);
#endif
],,
LIBS="-ltermcap $olibs"
AC_CHECKING(libtermcap)
AC_TRY_LINK(,tgetent((char *)0, (char *)0);,,
LIBS="-ltermlib $olibs"
AC_CHECKING(libtermlib)
AC_TRY_LINK(,tgetent((char *)0, (char *)0);,,
LIBS="-lncursesw $olibs"
AC_CHECKING(libncursesw)
AC_TRY_LINK(,tgetent((char *)0, (char *)0);,,
LIBS="-ltinfow $olibs"
AC_CHECKING(libtinfow)
AC_TRY_LINK(,tgetent((char *)0, (char *)0);,,
LIBS="-lncurses $olibs"
AC_CHECKING(libncurses)
AC_TRY_LINK(,tgetent((char *)0, (char *)0);,,
LIBS="-ltinfo $olibs"
AC_CHECKING(libtinfo)
AC_TRY_LINK(,tgetent((char *)0, (char *)0);,,
AC_MSG_ERROR(!!! no tgetent - no screen)))))))))

AC_TRY_RUN([
main()
{
 exit(strcmp(tgoto("%p1%d", 0, 1), "1") ? 0 : 1);
}], AC_NOTE(- you use the termcap database),
AC_NOTE(- you use the terminfo database) AC_DEFINE(TERMINFO),
AC_NOTE(- skipping check because we are cross compiling; assuming terminfo database is used) AC_DEFINE(TERMINFO))
AC_CHECKING(ospeed)
AC_TRY_LINK(extern short ospeed;,ospeed=5;,,AC_DEFINE(NEED_OSPEED))

dnl
dnl    ****  PTY specific things  ****
dnl
if test "$cross_compiling" = no ; then
AC_CHECKING(for /dev/ptc)
if test -r /dev/ptc; then
AC_DEFINE(HAVE_DEV_PTC)
fi
fi

if test "$cross_compiling" = no ; then
AC_CHECKING(for SVR4 ptys)
sysvr4ptys=
if test -c /dev/ptmx ; then
AC_TRY_LINK([],[ptsname(0);grantpt(0);unlockpt(0);],[AC_DEFINE(HAVE_SVR4_PTYS)
sysvr4ptys=1])
fi
fi

AC_CHECK_FUNCS(getpt)

dnl check for openpty()
if test -z "$sysvr4ptys"; then
AC_CHECK_FUNCS(openpty,,
[AC_CHECK_LIB(util,openpty, [AC_DEFINE(HAVE_OPENPTY)] [LIBS="$LIBS -lutil"])])
fi

if test "$cross_compiling" = no ; then
AC_CHECKING(for ptyranges)
if test -d /dev/ptym ; then
pdir='/dev/ptym'
else
pdir='/dev'
fi
dnl SCO uses ptyp%d
AC_EGREP_CPP(YES_IS_DEFINED,
[#ifdef M_UNIX
   YES_IS_DEFINED;
#endif
], ptys=`echo /dev/ptyp??`, ptys=`echo $pdir/pty??`)
dnl if test -c /dev/ptyp19; then
dnl ptys=`echo /dev/ptyp??`
dnl else
dnl ptys=`echo $pdir/pty??`
dnl fi
if test "$ptys" != "$pdir/pty??" ; then
p0=`echo $ptys | tr ' ' '\012' | sed -e 's/^.*\(.\).$/\1/g' | sort -u | tr -d '\012'`
p1=`echo $ptys | tr ' ' '\012' | sed -e 's/^.*\(.\)$/\1/g'  | sort -u | tr -d '\012'`
AC_DEFINE_UNQUOTED(PTYRANGE0,"$p0")
AC_DEFINE_UNQUOTED(PTYRANGE1,"$p1")
fi
fi

dnl    ****  pty mode/group handling ****
dnl
dnl support provided by Luke Mewburn <lm@rmit.edu.au>, 931222
AC_ARG_WITH(pty-mode, [  --with-pty-mode=mode    default mode for ptys], [ ptymode="${withval}" ])
AC_ARG_WITH(pty-group, [  --with-pty-group=group  default group for ptys], [ ptygrp="${withval}" ])
test -n "$ptymode" || ptymode=0620
if test -n "$ptygrp" ; then
AC_DEFINE_UNQUOTED(PTYMODE, $ptymode)
AC_DEFINE_UNQUOTED(PTYGROUP,$ptygrp)
else

AC_CHECKING(default tty permissions/group)
rm -f conftest_grp
AC_TRY_RUN([
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
main()
{
  struct stat sb;
  char *x,*ttyname();
  int om, m;
  FILE *fp;

  if (!(x = ttyname(0))) exit(1);
  if (stat(x, &sb)) exit(1);
  om = sb.st_mode;
  if (om & 002) exit(0);
  m = system("mesg y");
  if (m == -1 || m == 127) exit(1);
  if (stat(x, &sb)) exit(1);
  m = sb.st_mode;
  if (chmod(x, om)) exit(1);
  if (m & 002) exit(0);
  if (sb.st_gid == getgid()) exit(1);
  if (!(fp=fopen("conftest_grp", "w")))
    exit(1);
  fprintf(fp, "%d\n", sb.st_gid);
  fclose(fp);
  exit(0);
}
],[
    if test -f conftest_grp; then
	ptygrp=`cat conftest_grp`
	AC_NOTE([- pty mode: $ptymode, group: $ptygrp])
	AC_DEFINE_UNQUOTED(PTYMODE, $ptymode)
	AC_DEFINE_UNQUOTED(PTYGROUP,$ptygrp)
    else
	AC_NOTE(- ptys are world accessable)
    fi
],[
    WRITEPATH=''
    XTERMPATH=''
    AC_PATH_PROG(WRITEPATH, write)
    AC_PATH_PROG(XTERMPATH, xterm)
    found=
    if test -n "$WRITEPATH$XTERMPATH"; then
      findfollow=
      lsfollow=
      found=`find $WRITEPATH $XTERMPATH -follow -print 2>/dev/null`
      if test -n "$found"; then
	findfollow=-follow
	lsfollow=L
      fi
      if test -n "$XTERMPATH"; then
	ptygrpn=`ls -l$lsfollow $XTERMPATH | sed -n -e 1p | $AWK '{print $4}'`
	if test tty != "$ptygrpn"; then
	  XTERMPATH=
	fi
      fi
    fi
    if test -n "$WRITEPATH$XTERMPATH"; then
      found=`find $WRITEPATH $XTERMPATH $findfollow -perm -2000 -print` 
      if test -n "$found"; then
	ptygrp=`ls -ln$lsfollow $found | sed -n -e 1p | $AWK '{print $4}'`
	AC_NOTE([- pty mode: $ptymode, group: $ptygrp])
	AC_DEFINE_UNQUOTED(PTYMODE, $ptymode)
	AC_DEFINE_UNQUOTED(PTYGROUP,$ptygrp)
      else
	AC_NOTE(- ptys are world accessable)
      fi
    else
      AC_NOTE(- can't determine - assume ptys are world accessable)
    fi
  ],
  AC_NOTE(- skipping check because we are cross compiling; assuming ptys are world accessable)
)
rm -f conftest_grp
fi

dnl
dnl    ****  utmp handling  ****
dnl
AC_CHECKING(getutent)
AC_TRY_LINK([
#include <time.h> /* to get time_t on SCO */
#include <sys/types.h>
#if defined(SVR4) && !defined(DGUX)
#include <utmpx.h>
#define utmp utmpx
#else
#include <utmp.h>
#endif
#ifdef __hpux
#define pututline _pututline
#endif
],
[int x = DEAD_PROCESS; pututline((struct utmp *)0); getutent();], AC_DEFINE(GETUTENT),
olibs="$LIBS"
LIBS="$LIBS -lgen"
AC_CHECKING(getutent with -lgen)
AC_TRY_LINK([
#include <time.h>
#include <sys/types.h>
#if defined(SVR4) && !defined(DGUX)
#include <utmpx.h>
#define utmp utmpx
#else
#include <utmp.h>
#endif
#ifdef __hpux
#define pututline _pututline
#endif
],
[int x = DEAD_PROCESS; pututline((struct utmp *)0); getutent();], AC_DEFINE(GETUTENT), LIBS="$olibs")
)
AC_CHECKING(ut_host)
AC_TRY_COMPILE([
#include <time.h>
#include <sys/types.h>
#if defined(SVR4) && !defined(DGUX)
#include <utmpx.h>
#define utmp utmpx
#else
#include <utmp.h>
#endif
],[struct utmp u; u.ut_host[0] = 0;], AC_DEFINE(UTHOST))
AC_CHECK_HEADER(utempter.h, have_utempter=yes, have_utempter=no)
if test "$have_utempter" = yes; then
  AC_DEFINE(HAVE_UTEMPTER)
  LIBS="$LIBS -lutempter"
fi

dnl
dnl    ****  loadav  ****
dnl
if test "$cross_compiling" = no ; then
AC_CHECKING(for libutil(s))
test -f /usr/lib/libutils.a && LIBS="$LIBS -lutils"
test -f /usr/lib/libutil.a && LIBS="$LIBS -lutil"
fi

AC_CHECKING(getloadavg)
AC_TRY_LINK(,[getloadavg((double *)0, 0);],
AC_DEFINE(LOADAV_GETLOADAVG) load=1,
if test "$cross_compiling" = no && test -f /usr/lib/libkvm.a ; then
olibs="$LIBS"
LIBS="$LIBS -lkvm"
AC_CHECKING(getloadavg with -lkvm)
AC_TRY_LINK(,[getloadavg((double *)0, 0);],
AC_DEFINE(LOADAV_GETLOADAVG) load=1, LIBS="$olibs")
fi
)

if test -z "$load" ; then
AC_EGREP_CPP(YES_IS_DEFINED,
[#if defined(NeXT) || defined(apollo) || defined(linux)
  YES_IS_DEFINED;
#endif
], load=1)
fi
if test -z "$load" && test "$cross_compiling" = no ; then
AC_CHECKING(for kernelfile)
for core in /unix /vmunix /dynix /hp-ux /xelos /dev/ksyms /kernel/unix /kernel/genunix /unicos /mach /netbsd /386bsd /dgux /bsd /stand/vmunix; do
  if test -f $core || test -c $core; then
    break
  fi
done
if test ! -f $core && test ! -c $core ; then
  AC_NOTE(- no kernelfile found)
else
  AC_NOTE(- using kernelfile '$core')
  if test -r $core ; then
  AC_DEFINE_UNQUOTED(LOADAV_UNIX,"$core")
  AC_CHECK_HEADER(nlist.h,
    [AC_DEFINE(NLIST_STRUCT)
     AC_CHECKING(n_un in struct nlist)
     AC_TRY_COMPILE([#include <nlist.h>],
       [struct nlist n; n.n_un.n_name = 0;],
        AC_DEFINE(NLIST_NAME_UNION))])

  AC_CHECKING(for nlist declaration)
  AC_EGREP_CPP([nlist(( |	)( |	)*.*\(|\()],[
#ifdef NLIST_STRUCT
# include <nlist.h>
#else
# include <a.out.h>
#endif
],AC_DEFINE(NLIST_DECLARED))

  AC_CHECKING(for avenrun symbol)
  nlist64=
  for av in avenrun _avenrun _Loadavg avenrun _avenrun _Loadavg; do
  AC_TRY_RUN([
#include <sys/types.h>
#ifdef NLIST_STRUCT
#include <nlist.h>
#else
#include <a.out.h>
#endif

$nlist64

struct nlist nl[2];

main()
{
#if !defined(_AUX_SOURCE) && !defined(AUX)
# ifdef NLIST_NAME_UNION
  nl[0].n_un.n_name = "$av";
# else
  nl[0].n_name = "$av";
# endif
#else
  strncpy(nl[0].n_name, "$av", sizeof(nl[0].n_name));
#endif
  nlist(LOADAV_UNIX, nl);
  if (nl[0].n_value == 0)
    exit(1);
  exit(0);
}
  ],avensym=$av;break)
  if test "$av" = _Loadavg; then
    nlist64='#define nlist nlist64'
  fi
  done
  if test -z "$avensym" ; then
    AC_NOTE(- no avenrun symbol found)
  else
    AC_NOTE(- using avenrun symbol '$avensym')
    AC_DEFINE_UNQUOTED(LOADAV_AVENRUN,"$avensym")
    if test -n "$nlist64"; then
      AC_NOTE(- used nlist64 to find it)
      AC_DEFINE(LOADAV_USE_NLIST64)
    fi
    load=1
  fi
  else
    AC_NOTE(  Can't configure the load average display feature)
    AC_NOTE(  because $core is not readable by you.)
    AC_NOTE(  To configure the load average display feature,)
    AC_NOTE(  re-run configure as root if possible.)
    AC_NOTE(  If you are not the system administrator then disregard)
    AC_NOTE(  this warning.  You can still use screen without)
    AC_NOTE(  the load average display feature.)
  fi
fi
fi

AC_PROGRAM_SOURCE([
#include <sys/types.h>
#include <sys/param.h>
],[
#if !defined(LOADAV_GETLOADAVG) && ((defined(hp300) && !defined(__hpux)) || defined(sun) || (defined(ultrix) && defined(mips)) || defined(_SEQUENT_) || defined(sgi) || (defined(SVR4) && !defined(__hpux)) || defined(sony_news) || (!defined(__osf__) && defined(__alpha)) || defined(_IBMR2) || defined(_AUX_SOURCE) || defined(AUX) || defined(m88k))
loadtype=long
# if defined(apollo) || defined(_IBMR2) || defined(_AUX_SOURCE) || defined(AUX)
loadscale=65536
# else
#  if defined(FSCALE) && !defined(__osf__)
#   undef FSCALE
loadscale=FSCALE
#  else
#   ifdef sgi
loadtype=int
loadscale=1024
#   else
#    if defined(MIPS) || defined(SVR4) || defined(m88k)
loadscale=256
#    else /* not MIPS */
loadscale=1000 	/* our default value */
#    endif /* MIPS */
#   endif /* sgi */
#  endif /* not FSCALE */
# endif /* not apollo */
#else
loadtype=double
loadscale=1
#endif
#ifdef alliant
loadnum=4
#else
loadnum=3
#endif
])

if test -n "$load" ; then AC_DEFINE(LOADAV) fi
if test -n "$loadtype" ; then AC_DEFINE_UNQUOTED(LOADAV_TYPE,$loadtype) fi
if test -n "$loadnum" ; then AC_DEFINE_UNQUOTED(LOADAV_NUM,$loadnum) fi
if test -n "$loadscale" ; then AC_DEFINE_UNQUOTED(LOADAV_SCALE,$loadscale) fi

dnl
dnl    ****  signal handling  ****
dnl
if test -n "$posix" ; then

dnl POSIX has reliable signals with void return type.
AC_NOTE(assuming posix signal definition)
AC_DEFINE(SIGVOID)

else

AC_CHECKING(return type of signal handlers)
AC_TRY_COMPILE(
[#include <sys/types.h>
#include <signal.h>
#ifdef signal
#undef signal
#endif
extern void (*signal ()) ();], [int i;], AC_DEFINE(SIGVOID))
AC_CHECKING(sigset)
AC_TRY_LINK([
#include <sys/types.h>
#include <signal.h>
],[
#ifdef SIGVOID
sigset(0, (void (*)())0);
#else
sigset(0, (int (*)())0);
#endif
], AC_DEFINE(USESIGSET))
AC_CHECKING(signal implementation)
AC_TRY_RUN([
#include <sys/types.h>
#include <signal.h>

#ifndef SIGCLD
#define SIGCLD SIGCHLD
#endif
#ifdef USESIGSET
#define signal sigset
#endif

int got;

#ifdef SIGVOID
void
#endif
hand()
{
  got++;
}

main()
{
  /* on hpux we use sigvec to get bsd signals */
#ifdef __hpux
  (void)signal(SIGCLD, hand);
  kill(getpid(), SIGCLD);
  kill(getpid(), SIGCLD);
  if (got < 2)
    exit(1);
#endif
  exit(0);
}
],,AC_DEFINE(SYSVSIGS),:)

fi

dnl
dnl    ****  libraries  ****
dnl

AC_CHECKING(for crypt and sec libraries)
if test "$cross_compiling" = no ; then
test -f /lib/libcrypt_d.a || test -f /usr/lib/libcrypt_d.a && LIBS="$LIBS -lcrypt_d"
fi
oldlibs="$LIBS"
LIBS="$LIBS -lcrypt"
AC_CHECKING(crypt)
AC_TRY_LINK(,,,LIBS="$oldlibs")
if test "$cross_compiling" = no ; then
test -f /lib/libsec.a || test -f /usr/lib/libsec.a && LIBS="$LIBS -lsec"
test -f /lib/libshadow.a || test -f /usr/lib/libshadow.a && LIBS="$LIBS -lshadow"
fi

oldlibs="$LIBS"
LIBS="$LIBS -lsun"
AC_CHECKING(IRIX sun library)
AC_TRY_LINK(,,,LIBS="$oldlibs")

AC_CHECKING(syslog)
AC_TRY_LINK(,[closelog();], , [oldlibs="$LIBS"
LIBS="$LIBS -lbsd"
AC_CHECKING(syslog in libbsd.a)
AC_TRY_LINK(, [closelog();], AC_NOTE(- found.), [LIBS="$oldlibs"
AC_NOTE(- bad news: syslog missing.) AC_DEFINE(NOSYSLOG)])])

AC_EGREP_CPP(YES_IS_DEFINED,
[#ifdef M_UNIX
   YES_IS_DEFINED;
#endif
], LIBS="$LIBS -lsocket -lcrypt_i")

dnl
dnl    ****  misc things  ****
dnl
AC_CHECKING(wait union)
AC_TRY_COMPILE([#include <sys/types.h>
#include <sys/wait.h>
],[
  union wait x;
  int y;
#ifdef WEXITSTATUS
  y = WEXITSTATUS(x);
#endif
],AC_DEFINE(BSDWAIT))

if test -z "$butterfly"; then
AC_CHECKING(for termio or termios)
AC_TRY_CPP([#include <termio.h>], AC_DEFINE(TERMIO),
if test -n "$posix"; then
AC_TRY_CPP([#include <termios.h>], AC_DEFINE(TERMIO))
fi
)
fi

dnl AC_CHECK_HEADER(shadow.h, AC_DEFINE(SHADOWPW))
AC_CHECKING(getspnam)
AC_TRY_LINK([#include <shadow.h>], [getspnam("x");],AC_DEFINE(SHADOWPW))

AC_CHECKING(getttyent)
AC_TRY_LINK(,[getttyent();], AC_DEFINE(GETTTYENT))

AC_CHECKING(fdwalk)
AC_TRY_LINK([#include <stdlib.h>], [fdwalk(NULL, NULL);],AC_DEFINE(HAVE_FDWALK))

AC_CHECKING(whether memcpy/memmove/bcopy handles overlapping arguments)
AC_TRY_RUN([
main() {
  char buf[10];
  strcpy(buf, "abcdefghi");
  bcopy(buf, buf + 2, 3);
  if (strncmp(buf, "ababcf", 6))
    exit(1);
  strcpy(buf, "abcdefghi");
  bcopy(buf + 2, buf, 3);
  if (strncmp(buf, "cdedef", 6))
    exit(1);
  exit(0); /* libc version works properly.  */
}], AC_DEFINE(USEBCOPY),,:)

AC_TRY_RUN([
#define bcopy(s,d,l) memmove(d,s,l)
main() {
  char buf[10];
  strcpy(buf, "abcdefghi");
  bcopy(buf, buf + 2, 3);
  if (strncmp(buf, "ababcf", 6))
    exit(1);
  strcpy(buf, "abcdefghi");
  bcopy(buf + 2, buf, 3);
  if (strncmp(buf, "cdedef", 6))
    exit(1);
  exit(0); /* libc version works properly.  */
}], AC_DEFINE(USEMEMMOVE),,
  AC_NOTE(- skipping check because we are cross compiling; use memmove) AC_DEFINE(USEMEMMOVE))


AC_TRY_RUN([
#define bcopy(s,d,l) memcpy(d,s,l)
main() {
  char buf[10];
  strcpy(buf, "abcdefghi");
  bcopy(buf, buf + 2, 3);
  if (strncmp(buf, "ababcf", 6))
    exit(1);
  strcpy(buf, "abcdefghi");
  bcopy(buf + 2, buf, 3);
  if (strncmp(buf, "cdedef", 6))
    exit(1);
  exit(0); /* libc version works properly.  */
}], AC_DEFINE(USEMEMCPY),,:)

AC_SYS_LONG_FILE_NAMES

AC_MSG_CHECKING(for vsprintf)
AC_TRY_LINK([#include <stdarg.h>],[va_list valist; vsprintf(0,0,valist);], AC_MSG_RESULT(yes);AC_DEFINE(USEVARARGS), AC_MSG_RESULT(no))

AC_HEADER_DIRENT

AC_MSG_CHECKING(for setenv)
if test -z "$ac_setenv_args"; then
    AC_TRY_LINK(
    [#include <stdlib.h>],
    [
        setenv((char *) 0, (char *) 0, 0);
    ], ac_setenv_args=3)
fi
if test -z "$ac_setenv_args"; then
    AC_TRY_LINK(
    [#include <stdlib.h>],
    [
        setenv((char *) 0, (char *) 0);
    ], ac_setenv_args=2)
fi
if test -n "$ac_setenv_args"; then
    AC_DEFINE(USESETENV)
    if test "$ac_setenv_args" = 3; then
        AC_DEFINE(HAVE_SETENV_3)
    elif test "$ac_setenv_args" = 2; then
        AC_DEFINE(HAVE_SETENV_2)
    fi
else
    AC_MSG_RESULT(no)
    AC_MSG_CHECKING(for putenv)
    AC_TRY_LINK(,[putenv((char *)0);unsetenv((char *)0);], AC_MSG_RESULT(yes) ,  AC_MSG_RESULT(no);AC_DEFINE(NEEDPUTENV))
fi
AC_MSG_CHECKING([for nl_langinfo(CODESET)])
AC_TRY_LINK([
#include <langinfo.h>
],[nl_langinfo(CODESET);], AC_MSG_RESULT(yes);AC_DEFINE(HAVE_NL_LANGINFO), AC_MSG_RESULT(no))

AC_SEARCH_LIBS(gethostname, nsl)

AC_CHECK_FUNCS(rename fchmod fchown strerror lstat _exit utimes vsnprintf getcwd setlocale strftime)

AC_ARG_ENABLE(pam, [  --enable-pam            enable PAM support])
if test "$enable_pam" = "yes"; then
    AC_MSG_CHECKING(for PAM support)
    oldlibs="$LIBS"
    LIBS="$LIBS -lpam"
    AC_TRY_LINK([#include <security/pam_appl.h>], [
	pam_start(0, 0, 0, 0);
	pam_authenticate(0, 0);
	pam_end(0,0);
    ], AC_MSG_RESULT(yes);AC_DEFINE(USE_PAM),
       AC_MSG_RESULT(no);LIBS="$oldlibs")
fi

AC_ARG_ENABLE(use-locale,
    [  --enable-use-locale     use localized month/day names (default: yes)],
    [],
    [enable_use_locale=yes]
)
if test "$enable_use_locale" = "yes"; then
  AC_DEFINE(USE_LOCALE)
fi
AC_ARG_ENABLE(telnet, [  --enable-telnet         enable builtin telnet])
if test "$enable_telnet" = "yes"; then
  AC_DEFINE(BUILTIN_TELNET)
fi
AC_ARG_ENABLE(colors256, [  --enable-colors256      enable support for 256 colors])
if test "$enable_colors256" = "yes"; then
  AC_DEFINE(COLORS256)
fi
AC_ARG_ENABLE(rxvt_osc, [  --enable-rxvt_osc       enable support for rxvt OSC codes])
if test "$enable_rxvt_osc" = "yes"; then
  AC_DEFINE(RXVT_OSC)
fi

dnl
dnl    ****  the end  ****
dnl
if test -z "$old_CFLAGS"; then
  if test "x$CFLAGS" = "x-g"; then
    CFLAGS="-O"
  fi
fi
dnl Ptx bug workaround -- insert -lc after -ltermcap
test -n "$seqptx" && LIBS="-ltermcap -lc -lsocket -linet -lnsl -lsec -lseq"

ETCSCREENRC=
AC_MSG_CHECKING(for the global screenrc file)
AC_ARG_WITH(sys-screenrc, [  --with-sys-screenrc=path to the global screenrc file], [ ETCSCREENRC="${withval}" ])
AC_SUBST(ETCSCREENRC)

AC_OUTPUT(Makefile doc/Makefile, [[
# a hook for preserving undef directive in config.h
mv config.h conftest
sed -e 's@^\(.*\)defin.\( .*\) .*/\*\(.*KEEP_UNDEF_HERE\)@\1undef\2	/\*\3@' < conftest > config.h
rm -f conftest
]])

echo ""
if test -z "$AWK"; then
echo "!!! Since you have no awk you must copy the files 'comm.h.dist'"
echo "!!! and 'term.h.dist' to 'comm.h' and 'term.h'."
echo "!!! Do _not_ change the user configuration section in config.h!"
echo "Please check the pathnames in the Makefile."
else
echo "Now please check the pathnames in the Makefile and in the user"
echo "configuration section in config.h."
fi
echo "Then type 'make' to make screen. Good luck."
echo ""