path: root/unix/configure.in

dnl	This file is an input file used by the GNU "autoconf" program to
dnl	generate the file "configure", which is run during Tcl installation
dnl	to configure the system for the local environment.
AC_INIT(../generic/tcl.h)
# RCS: @(#) $Id: configure.in,v 1.35 1999/04/30 23:35:40 stanton Exp $

TCL_VERSION=8.1
TCL_MAJOR_VERSION=8
TCL_MINOR_VERSION=1
TCL_PATCH_LEVEL=1
VERSION=${TCL_VERSION}

if test "${prefix}" = "NONE"; then
    prefix=/usr/local
fi
if test "${exec_prefix}" = "NONE"; then
    exec_prefix=$prefix
fi
TCL_SRC_DIR=`cd $srcdir/..; pwd`

AC_PROG_RANLIB
AC_ARG_ENABLE(gcc, [  --enable-gcc            allow use of gcc if available],
    [tcl_ok=$enableval], [tcl_ok=no])
if test "$tcl_ok" = "yes"; then
    AC_PROG_CC
else
    CC=${CC-cc}
AC_SUBST(CC)
fi
AC_C_CROSS

# Threads support
AC_ARG_ENABLE(threads,[  --enable-threads        enable Threads support],,enableval="no")

if test "$enableval" = "yes"; then
  AC_MSG_RESULT(Will compile with Threads support)
  AC_DEFINE(TCL_THREADS)
  AC_DEFINE(_REENTRANT)

  AC_CHECK_LIB(pthread,pthread_mutex_init,tcl_ok=yes,tcl_ok=no)
  if test "$tcl_ok" = "yes"; then
     # The space is needed
     THREADS_LIBS=" -lpthread"
  else
     AC_MSG_WARN("Don t know how to find pthread lib on your system - you must disable thread support or edit the LIBS in the Makefile...")
  fi
else
  AC_MSG_RESULT(Will compile without Threads support (normal))
fi

# set the warning flags depending on whether or not we are using gcc
if test "${GCC}" = "yes" ; then
    CFLAGS_WARNING="-Wall -Wconversion"
else
    CFLAGS_WARNING=""
fi

#-----------------------------
# 64-bit support
#-----------------------------

AC_ARG_ENABLE(64bit,[  --enable-64bit          enable 64bit support],,enableval="no")

if test "$enableval" = "yes"; then
  AC_MSG_RESULT(Will compile with 64bit support)
  do64bit=yes
else
  do64bit=no
fi

#------------------------------------------------------------------------------
# If we're using GCC, see if the compiler understands -pipe.  If so, use it.
# It makes compiling go faster.  (This is only a performance feature.)
#------------------------------------------------------------------------------

if test -z "$no_pipe"; then
if test -n "$GCC"; then
  AC_MSG_CHECKING([if the compiler understands -pipe])
  OLDCC="$CC"  
  CC="$CC -pipe"
  AC_TRY_COMPILE(,,
    AC_MSG_RESULT(yes),
    CC="$OLDCC"
    AC_MSG_RESULT(no))
fi  
fi

#--------------------------------------------------------------------
#	Supply substitutes for missing POSIX library procedures, or
#	set flags so Tcl uses alternate procedures.
#--------------------------------------------------------------------

# Check if Posix compliant getcwd exists, if not we'll use getwd.
AC_CHECK_FUNCS(getcwd, , AC_DEFINE(USEGETWD))
# Nb: if getcwd uses popen and pwd(1) (like SunOS 4) we should really
# define USEGETWD even if the posix getcwd exists. Add a test ?

AC_REPLACE_FUNCS(opendir strstr)

AC_REPLACE_FUNCS(strtol tmpnam waitpid)
AC_CHECK_FUNC(strerror, , AC_DEFINE(NO_STRERROR))
AC_CHECK_FUNC(getwd, , AC_DEFINE(NO_GETWD))
AC_CHECK_FUNC(wait3, , AC_DEFINE(NO_WAIT3))
AC_CHECK_FUNC(uname, , AC_DEFINE(NO_UNAME))
AC_CHECK_FUNC(realpath, , AC_DEFINE(NO_REALPATH))

#--------------------------------------------------------------------
#	On a few very rare systems, all of the libm.a stuff is
#	already in libc.a.  Set compiler flags accordingly.
#	Also, Linux requires the "ieee" library for math to work
#	right (and it must appear before "-lm").
#--------------------------------------------------------------------

AC_CHECK_FUNC(sin, MATH_LIBS="", MATH_LIBS="-lm")
AC_CHECK_LIB(ieee, main, [MATH_LIBS="-lieee $MATH_LIBS"])

#--------------------------------------------------------------------
#       On AIX systems, libbsd.a has to be linked in to support
#       non-blocking file IO.  This library has to be linked in after
#       the MATH_LIBS or it breaks the pow() function.  The way to
#       insure proper sequencing, is to add it to the tail of MATH_LIBS.
#        This library also supplies gettimeofday.
#--------------------------------------------------------------------
libbsd=no
if test "`uname -s`" = "AIX" ; then
    AC_CHECK_LIB(bsd, gettimeofday, libbsd=yes)
    if test $libbsd = yes; then
	MATH_LIBS="$MATH_LIBS -lbsd"
    fi
fi

#--------------------------------------------------------------------
#	Supply substitutes for missing POSIX header files.  Special
#	notes:
#	    - stdlib.h doesn't define strtol, strtoul, or
#	      strtod insome versions of SunOS
#	    - some versions of string.h don't declare procedures such
#	      as strstr
#--------------------------------------------------------------------

AC_MSG_CHECKING(dirent.h)
AC_TRY_LINK([#include <sys/types.h>
#include <dirent.h>], [
#ifndef _POSIX_SOURCE
#   ifdef __Lynx__
	/*
	 * Generate compilation error to make the test fail:  Lynx headers
	 * are only valid if really in the POSIX environment.
	 */

	missing_procedure();
#   endif
#endif
DIR *d;
struct dirent *entryPtr;
char *p;
d = opendir("foobar");
entryPtr = readdir(d);
p = entryPtr->d_name;
closedir(d);
], tcl_ok=yes, tcl_ok=no)
if test $tcl_ok = no; then
    AC_DEFINE(NO_DIRENT_H)
fi
AC_MSG_RESULT($tcl_ok)
AC_CHECK_HEADER(errno.h, , AC_DEFINE(NO_ERRNO_H))
AC_CHECK_HEADER(float.h, , AC_DEFINE(NO_FLOAT_H))
AC_CHECK_HEADER(values.h, , AC_DEFINE(NO_VALUES_H))
AC_CHECK_HEADER(limits.h, , AC_DEFINE(NO_LIMITS_H))
AC_CHECK_HEADER(stdlib.h, tcl_ok=1, tcl_ok=0)
AC_EGREP_HEADER(strtol, stdlib.h, , tcl_ok=0)
AC_EGREP_HEADER(strtoul, stdlib.h, , tcl_ok=0)
AC_EGREP_HEADER(strtod, stdlib.h, , tcl_ok=0)
if test $tcl_ok = 0; then
    AC_DEFINE(NO_STDLIB_H)
fi
AC_CHECK_HEADER(string.h, tcl_ok=1, tcl_ok=0)
AC_EGREP_HEADER(strstr, string.h, , tcl_ok=0)
AC_EGREP_HEADER(strerror, string.h, , tcl_ok=0)
# See also memmove check below for a place where NO_STRING_H can be
# set and why.
if test $tcl_ok = 0; then
    AC_DEFINE(NO_STRING_H)
fi
AC_CHECK_HEADER(sys/wait.h, , AC_DEFINE(NO_SYS_WAIT_H))
AC_CHECK_HEADER(dlfcn.h, , AC_DEFINE(NO_DLFCN_H))

# OS/390 lacks sys/param.h (and doesn't need it, by chance).
AC_HAVE_HEADERS(unistd.h sys/param.h)

#---------------------------------------------------------------------------
#	Determine which interface to use to talk to the serial port.
#	Note that #include lines must begin in leftmost column for
#	some compilers to recognize them as preprocessor directives.
#---------------------------------------------------------------------------

AC_MSG_CHECKING([termios vs. termio vs. sgtty])
AC_TRY_RUN([
#include <termios.h>

main()
{
    struct termios t;
    if (tcgetattr(0, &t) == 0) {
	cfsetospeed(&t, 0);
	t.c_cflag |= PARENB | PARODD | CSIZE | CSTOPB;
	return 0;
    }
    return 1;
}], tk_ok=termios, tk_ok=no, tk_ok=no)
if test $tk_ok = termios; then
    AC_DEFINE(USE_TERMIOS)
else
AC_TRY_RUN([
#include <termio.h>

main()
{
    struct termio t;
    if (ioctl(0, TCGETA, &t) == 0) {
	t.c_cflag |= CBAUD | PARENB | PARODD | CSIZE | CSTOPB;
	return 0;
    }
    return 1;
}], tk_ok=termio, tk_ok=no, tk_ok=no)
if test $tk_ok = termio; then
    AC_DEFINE(USE_TERMIO)
else
AC_TRY_RUN([
#include <sgtty.h>

main()
{
    struct sgttyb t;
    if (ioctl(0, TIOCGETP, &t) == 0) {
	t.sg_ospeed = 0;
	t.sg_flags |= ODDP | EVENP | RAW;
	return 0;
    }
    return 1;
}], tk_ok=sgtty, tk_ok=none, tk_ok=none)
if test $tk_ok = sgtty; then
    AC_DEFINE(USE_SGTTY)
fi
fi
fi
AC_MSG_RESULT($tk_ok)

#--------------------------------------------------------------------
#	Include sys/select.h if it exists and if it supplies things
#	that appear to be useful and aren't already in sys/types.h.
#	This appears to be true only on the RS/6000 under AIX.  Some
#	systems like OSF/1 have a sys/select.h that's of no use, and
#	other systems like SCO UNIX have a sys/select.h that's
#	pernicious.  If "fd_set" isn't defined anywhere then set a
#	special flag.
#--------------------------------------------------------------------

AC_MSG_CHECKING([fd_set and sys/select])
AC_TRY_COMPILE([#include <sys/types.h>],
	[fd_set readMask, writeMask;], tk_ok=yes, tk_ok=no)
if test $tk_ok = no; then
    AC_HEADER_EGREP(fd_mask, sys/select.h, tk_ok=yes)
    if test $tk_ok = yes; then
	AC_DEFINE(HAVE_SYS_SELECT_H)
    fi
fi
AC_MSG_RESULT($tk_ok)
if test $tk_ok = no; then
    AC_DEFINE(NO_FD_SET)
fi

#------------------------------------------------------------------------------
#       Find out all about time handling differences.
#------------------------------------------------------------------------------

AC_CHECK_HEADERS(sys/time.h)
AC_HEADER_TIME
AC_STRUCT_TIMEZONE

AC_MSG_CHECKING([tm_tzadj in struct tm])
AC_TRY_COMPILE([#include <time.h>], [struct tm tm; tm.tm_tzadj;],
        [AC_DEFINE(HAVE_TM_TZADJ)
         AC_MSG_RESULT(yes)],
         AC_MSG_RESULT(no))

AC_MSG_CHECKING([tm_gmtoff in struct tm])
AC_TRY_COMPILE([#include <time.h>], [struct tm tm; tm.tm_gmtoff;],
        [AC_DEFINE(HAVE_TM_GMTOFF)
         AC_MSG_RESULT(yes)],
         AC_MSG_RESULT(no))

#
# Its important to include time.h in this check, as some systems (like convex)
# have timezone functions, etc.
#
have_timezone=no
AC_MSG_CHECKING([long timezone variable])
AC_TRY_COMPILE([#include <time.h>],
        [extern long timezone;
         timezone += 1;
         exit (0);],
        [have_timezone=yes
	 AC_DEFINE(HAVE_TIMEZONE_VAR)
         AC_MSG_RESULT(yes)],
         AC_MSG_RESULT(no))

#
# On some systems (eg IRIX 6.2), timezone is a time_t and not a long.
#
if test "$have_timezone" = no; then
   AC_MSG_CHECKING([time_t timezone variable])
   AC_TRY_COMPILE([#include <time.h>],
        [extern time_t timezone;
         timezone += 1;
         exit (0);],
        [AC_DEFINE(HAVE_TIMEZONE_VAR)
         AC_MSG_RESULT(yes)],
         AC_MSG_RESULT(no))
fi

#
# AIX does not have a timezone field in struct tm. When the AIX bsd
# library is used, the timezone global and the gettimeofday methods are
# to be avoided for timezone deduction instead, we deduce the timezone
# by comparing the localtime result on a known GMT value.
#
if test $libbsd = yes; then
    AC_DEFINE(USE_DELTA_FOR_TZ)
fi

#--------------------------------------------------------------------
#	Some systems (e.g., IRIX 4.0.5) lack the st_blksize field
#	in struct stat.  But we might be able to use fstatfs instead.
#--------------------------------------------------------------------
AC_STRUCT_ST_BLKSIZE
AC_CHECK_FUNC(fstatfs, , AC_DEFINE(NO_FSTATFS))

#--------------------------------------------------------------------
#       Some system have no memcmp or it does not work with 8 bit
#       data, this checks it and add memcmp.o to LIBOBJS if needed
#--------------------------------------------------------------------
AC_FUNC_MEMCMP

#--------------------------------------------------------------------
#       Some system like SunOS 4 and other BSD like systems
#       have no memmove (we assume they have bcopy instead).
#       {The replacement define is in compat/string.h}
#--------------------------------------------------------------------
AC_CHECK_FUNC(memmove, , AC_DEFINE(NO_MEMMOVE) AC_DEFINE(NO_STRING_H))

#--------------------------------------------------------------------
#	On some systems strstr is broken: it returns a pointer even
#	even if the original string is empty.
#--------------------------------------------------------------------

AC_MSG_CHECKING([proper strstr implementation])
AC_TRY_RUN([
extern int strstr();
int main()
{
    exit(strstr("\0test", "test") ? 1 : 0);
}
], tcl_ok=yes, tcl_ok=no, tcl_ok=no)
if test $tcl_ok = yes; then
    AC_MSG_RESULT(yes)
else
    AC_MSG_RESULT([broken, using substitute])
    LIBOBJS="$LIBOBJS strstr.o"
fi

#--------------------------------------------------------------------
#	Check for strtoul function.  This is tricky because under some
#	versions of AIX strtoul returns an incorrect terminator
#	pointer for the string "0".
#--------------------------------------------------------------------

AC_CHECK_FUNC(strtoul, tcl_ok=1, tcl_ok=0)
AC_TRY_RUN([
extern int strtoul();
int main()
{
    char *string = "0";
    char *term;
    int value;
    value = strtoul(string, &term, 0);
    if ((value != 0) || (term != (string+1))) {
        exit(1);
    }
    exit(0);
}], , tcl_ok=0, tcl_ok=0)
if test "$tcl_ok" = 0; then
    test -n "$verbose" && echo "	Adding strtoul.o."
    LIBOBJS="$LIBOBJS strtoul.o"
fi

#--------------------------------------------------------------------
#	Check for the strtod function.  This is tricky because in some
#	versions of Linux strtod mis-parses strings starting with "+".
#--------------------------------------------------------------------

AC_CHECK_FUNC(strtod, tcl_ok=1, tcl_ok=0)
AC_TRY_RUN([
extern double strtod();
int main()
{
    char *string = " +69";
    char *term;
    double value;
    value = strtod(string, &term);
    if ((value != 69) || (term != (string+4))) {
	exit(1);
    }
    exit(0);
}], , tcl_ok=0, tcl_ok=0)
if test "$tcl_ok" = 0; then
    test -n "$verbose" && echo "	Adding strtod.o."
    LIBOBJS="$LIBOBJS strtod.o"
fi

#--------------------------------------------------------------------
#	Under Solaris 2.4, strtod returns the wrong value for the
#	terminating character under some conditions.  Check for this
#	and if the problem exists use a substitute procedure
#	"fixstrtod" that corrects the error.
#--------------------------------------------------------------------

AC_CHECK_FUNC(strtod, tcl_strtod=1, tcl_strtod=0)
if test "$tcl_strtod" = 1; then
    AC_MSG_CHECKING([for Solaris strtod bug])
    AC_TRY_RUN([
extern double strtod();
int main()
{
    char *string = "NaN";
    char *term;
    strtod(string, &term);
    if ((term != string) && (term[-1] == 0)) {
	exit(1);
    }
    exit(0);
}], tcl_ok=1, tcl_ok=0, tcl_ok=0)
    if test $tcl_ok = 1; then
	AC_MSG_RESULT(ok)
    else
	AC_MSG_RESULT(buggy)
	LIBOBJS="$LIBOBJS fixstrtod.o"
	AC_DEFINE(strtod, fixstrtod)
    fi
fi

#--------------------------------------------------------------------
#	Check for various typedefs and provide substitutes if
#	they don't exist.
#--------------------------------------------------------------------

AC_TYPE_MODE_T
AC_TYPE_PID_T
AC_TYPE_SIZE_T
AC_TYPE_UID_T

#--------------------------------------------------------------------
#	If a system doesn't have an opendir function (man, that's old!)
#	then we have to supply a different version of dirent.h which
#	is compatible with the substitute version of opendir that's
#	provided.  This version only works with V7-style directories.
#--------------------------------------------------------------------

AC_CHECK_FUNC(opendir, , AC_DEFINE(USE_DIRENT2_H))

#--------------------------------------------------------------------
#	The check below checks whether <sys/wait.h> defines the type
#	"union wait" correctly.  It's needed because of weirdness in
#	HP-UX where "union wait" is defined in both the BSD and SYS-V
#	environments.  Checking the usability of WIFEXITED seems to do
#	the trick.
#--------------------------------------------------------------------

AC_MSG_CHECKING([union wait])
AC_TRY_LINK([#include <sys/types.h> 
#include <sys/wait.h>], [
union wait x;
WIFEXITED(x);		/* Generates compiler error if WIFEXITED
			 * uses an int. */
], tcl_ok=yes, tcl_ok=no)
AC_MSG_RESULT($tcl_ok)
if test $tcl_ok = no; then
    AC_DEFINE(NO_UNION_WAIT)
fi

#--------------------------------------------------------------------
#	Check to see whether the system supports the matherr function
#	and its associated type "struct exception".
#--------------------------------------------------------------------

AC_MSG_CHECKING([matherr support])
AC_TRY_COMPILE([#include <math.h>], [
struct exception x;
x.type = DOMAIN;
x.type = SING;
], tcl_ok=yes, tcl_ok=no)
AC_MSG_RESULT($tcl_ok)
if test $tcl_ok = yes; then
    AC_DEFINE(NEED_MATHERR)
fi

#--------------------------------------------------------------------
#	Check to see whether the system provides a vfork kernel call.
#	If not, then use fork instead.  Also, check for a problem with
#	vforks and signals that can cause core dumps if a vforked child
#	resets a signal handler.  If the problem exists, then use fork
#	instead of vfork.
#--------------------------------------------------------------------

AC_TYPE_SIGNAL()
AC_CHECK_FUNC(vfork, tcl_ok=1, tcl_ok=0)
if test "$tcl_ok" = 1; then
    AC_MSG_CHECKING([vfork/signal bug]);
    AC_TRY_RUN([
#include <stdio.h>
#include <signal.h>
#include <sys/wait.h>
int gotSignal = 0;
sigProc(sig)
    int sig;
{
    gotSignal = 1;
}
main()
{
    int pid, sts;
    (void) signal(SIGCHLD, sigProc);
    pid = vfork();
    if (pid <  0) {
	exit(1);
    } else if (pid == 0) {
	(void) signal(SIGCHLD, SIG_DFL);
	_exit(0);
    } else {
	(void) wait(&sts);
    }
    exit((gotSignal) ? 0 : 1);
}], tcl_ok=1, tcl_ok=0, tcl_ok=0)
    if test "$tcl_ok" = 1; then
	AC_MSG_RESULT(ok)
    else
	AC_MSG_RESULT([buggy, using fork instead])
    fi
fi
rm -f core
if test "$tcl_ok" = 0; then
    AC_DEFINE(vfork, fork)
fi

#--------------------------------------------------------------------
#	Check whether there is an strncasecmp function on this system.
#	This is a bit tricky because under SCO it's in -lsocket and
#	under Sequent Dynix it's in -linet.
#--------------------------------------------------------------------

AC_CHECK_FUNC(strncasecmp, tcl_ok=1, tcl_ok=0)
if test "$tcl_ok" = 0; then
    AC_CHECK_LIB(socket, strncasecmp, tcl_ok=1, tcl_ok=0)
fi
if test "$tcl_ok" = 0; then
    AC_CHECK_LIB(inet, strncasecmp, tcl_ok=1, tcl_ok=0)
fi
if test "$tcl_ok" = 0; then
    LIBOBJS="$LIBOBJS strncasecmp.o"
fi

#--------------------------------------------------------------------
#	The code below deals with several issues related to gettimeofday:
#	1. Some systems don't provide a gettimeofday function at all
#	   (set NO_GETTOD if this is the case).
#	2. SGI systems don't use the BSD form of the gettimeofday function,
#	   but they have a BSDgettimeofday function that can be used instead.
#	3. See if gettimeofday is declared in the <sys/time.h> header file.
#	   if not, set the GETTOD_NOT_DECLARED flag so that tclPort.h can
#	   declare it.
#--------------------------------------------------------------------

AC_CHECK_FUNC(BSDgettimeofday, AC_DEFINE(HAVE_BSDGETTIMEOFDAY),
	AC_CHECK_FUNC(gettimeofday, , AC_DEFINE(NO_GETTOD)))
AC_MSG_CHECKING([for gettimeofday declaration])
AC_EGREP_HEADER(gettimeofday, sys/time.h, AC_MSG_RESULT(present), [
    AC_MSG_RESULT(missing)
    AC_DEFINE(GETTOD_NOT_DECLARED)
])

#--------------------------------------------------------------------
#	Interactive UNIX requires -linet instead of -lsocket, plus it
#	needs net/errno.h to define the socket-related error codes.
#--------------------------------------------------------------------

AC_CHECK_LIB(inet, main, [LIBS="$LIBS -linet"])
AC_CHECK_HEADER(net/errno.h, AC_DEFINE(HAVE_NET_ERRNO_H))

#--------------------------------------------------------------------
#	The following code checks to see whether it is possible to get
#	signed chars on this platform.  This is needed in order to
#	properly generate sign-extended ints from character values.
#--------------------------------------------------------------------

AC_C_CHAR_UNSIGNED
AC_MSG_CHECKING([signed char declarations])
AC_TRY_COMPILE(, [
signed char *p;
p = 0;
], tcl_ok=yes, tcl_ok=no)
AC_MSG_RESULT($tcl_ok)
if test $tcl_ok = yes; then
    AC_DEFINE(HAVE_SIGNED_CHAR)
fi

#--------------------------------------------------------------------
#	Check for the existence of the -lsocket and -lnsl libraries.
#	The order here is important, so that they end up in the right
#	order in the command line generated by make.  Here are some
#	special considerations:
#	1. Use "connect" and "accept" to check for -lsocket, and
#	   "gethostbyname" to check for -lnsl.
#	2. Use each function name only once:  can't redo a check because
#	   autoconf caches the results of the last check and won't redo it.
#	3. Use -lnsl and -lsocket only if they supply procedures that
#	   aren't already present in the normal libraries.  This is because
#	   IRIX 5.2 has libraries, but they aren't needed and they're
#	   bogus:  they goof up name resolution if used.
#	4. On some SVR4 systems, can't use -lsocket without -lnsl too.
#	   To get around this problem, check for both libraries together
#	   if -lsocket doesn't work by itself.
#--------------------------------------------------------------------

tcl_checkBoth=0
AC_CHECK_FUNC(connect, tcl_checkSocket=0, tcl_checkSocket=1)
if test "$tcl_checkSocket" = 1; then
    AC_CHECK_LIB(socket, main, LIBS="$LIBS -lsocket", tcl_checkBoth=1)
fi
if test "$tcl_checkBoth" = 1; then
    tk_oldLibs=$LIBS
    LIBS="$LIBS -lsocket -lnsl"
    AC_CHECK_FUNC(accept, tcl_checkNsl=0, [LIBS=$tk_oldLibs])
fi
AC_CHECK_FUNC(gethostbyname, , AC_CHECK_LIB(nsl, main, [LIBS="$LIBS -lnsl"]))

# Add the threads support libraries

LIBS="$LIBS$THREADS_LIBS"

#--------------------------------------------------------------------
#	The statements below define a collection of symbols related to
#	dynamic loading and shared libraries:
#
#	DL_OBJS -	Name of the object file that implements dynamic
#			loading for Tcl on this system.
#	DL_LIBS -	Library file(s) to include in tclsh and other base
#			applications in order for the "load" command to work.
#	LD_FLAGS -	Flags to pass to the compiler when linking object
#			files into an executable application binary such
#			as tclsh.
#	LD_SEARCH_FLAGS-Flags to pass to ld, such as "-R /usr/local/tcl/lib",
#			that tell the run-time dynamic linker where to look
#			for shared libraries such as libtcl.so.  Depends on
#			the variable LIB_RUNTIME_DIR in the Makefile.
#	MAKE_LIB -	Command to execute to build the Tcl library;
#			differs depending on whether or not Tcl is being
#			compiled as a shared library.
#	SHLIB_CFLAGS -	Flags to pass to cc when compiling the components
#			of a shared library (may request position-independent
#			code, among other things).
#	SHLIB_LD -	Base command to use for combining object files
#			into a shared library.
#	SHLIB_LD_LIBS -	Dependent libraries for the linker to scan when
#			creating shared libraries.  This symbol typically
#			goes at the end of the "ld" commands that build
#			shared libraries. The value of the symbol is
#			"${LIBS}" if all of the dependent libraries should
#			be specified when creating a shared library.  If
#			dependent libraries should not be specified (as on
#			SunOS 4.x, where they cause the link to fail, or in
#			general if Tcl and Tk aren't themselves shared
#			libraries), then this symbol has an empty string
#			as its value.
#	SHLIB_SUFFIX -	Suffix to use for the names of dynamically loadable
#			extensions.  An empty string means we don't know how
#			to use shared libraries on this platform.
#	TCL_LIB_FILE -	Name of the file that contains the Tcl library, such
#			as libtcl7.8.so or libtcl7.8.a.
#	TCL_LIB_SUFFIX -Specifies everything that comes after the "libtcl"
#			in the shared library name, using the $VERSION variable
#			to put the version in the right place.  This is used
#			by platforms that need non-standard library names.
#			Examples:  ${VERSION}.so.1.1 on NetBSD, since it needs
#			to have a version after the .so, and ${VERSION}.a
#			on AIX, since the Tcl shared library needs to have
#			a .a extension whereas shared objects for loadable
#			extensions have a .so extension.  Defaults to
#			${VERSION}${SHLIB_SUFFIX}.
#	TCL_NEEDS_EXP_FILE -
#			1 means that an export file is needed to link to a
#			shared library.
#
#	TCL_EXP_FILE -  The name of the installed export / import file which 
#			should be used to link to the Tcl shared library.
#			Empty if Tcl is unshared.
#	TCL_BUILD_EXP_FILE -
#			The name of the built export / import file which
#			should be used to link to the Tcl shared library.
#			Empty if Tcl is unshared.
#--------------------------------------------------------------------

# Step 1: set the variable "system" to hold the name and version number
# for the system.  This can usually be done via the "uname" command, but
# there are a few systems, like Next, where this doesn't work.

AC_MSG_CHECKING([system version (for dynamic loading)])
if test -f /usr/lib/NextStep/software_version; then
    system=NEXTSTEP-`awk '/3/,/3/' /usr/lib/NextStep/software_version`
else
    system=`uname -s`-`uname -r`
    if test "$?" -ne 0 ; then
	AC_MSG_RESULT([unknown (can't find uname command)])
	system=unknown
    else
	# Special check for weird MP-RAS system (uname returns weird
	# results, and the version is kept in special file).
    
	if test -r /etc/.relid -a "X`uname -n`" = "X`uname -s`" ; then
	    system=MP-RAS-`awk '{print $3}' /etc/.relid'`
	fi
	if test "`uname -s`" = "AIX" ; then
	    system=AIX-`uname -v`.`uname -r`
	fi
	AC_MSG_RESULT($system)
    fi
fi

# Step 2: check for existence of -ldl library.  This is needed because
# Linux can use either -ldl or -ldld for dynamic loading.

AC_CHECK_LIB(dl, dlopen, have_dl=yes, have_dl=no)

# Step 3: set configuration options based on system name and version.

do64bit_ok=no
fullSrcDir=`cd $srcdir; pwd`
EXTRA_CFLAGS=""
TCL_EXPORT_FILE_SUFFIX=""
TCL_UNSHARED_LIB_SUFFIX=""
TCL_TRIM_DOTS='`echo ${VERSION} | tr -d .`'
ECHO_VERSION='`echo ${VERSION}`'
TCL_LIB_VERSIONS_OK=ok
CFLAGS_DEBUG=-g
CFLAGS_OPTIMIZE=-O
TCL_NEEDS_EXP_FILE=0
TCL_BUILD_EXP_FILE=""
TCL_EXP_FILE=""
case $system in
    AIX-4.[[2-9]])
	SHLIB_CFLAGS=""
	SHLIB_LD="$fullSrcDir/ldAix /bin/ld -bhalt:4 -bM:SRE -bE:lib.exp -H512 -T512 -bnoentry"
	SHLIB_LD_LIBS='${LIBS}'
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS="-ldl"
	LD_FLAGS=""
	LD_SEARCH_FLAGS='-L${LIB_RUNTIME_DIR}'
	TCL_NEEDS_EXP_FILE=1
	TCL_EXPORT_FILE_SUFFIX='${VERSION}\$\{DBGX\}.exp'
	;;
    AIX-*)
	SHLIB_CFLAGS=""
	SHLIB_LD="$fullSrcDir/ldAix /bin/ld -bhalt:4 -bM:SRE -bE:lib.exp -H512 -T512"
	SHLIB_LD_LIBS='${LIBS}'
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o tclLoadAix.o"
	DL_LIBS="-lld"
	LD_FLAGS=""
	LD_SEARCH_FLAGS='-L${LIB_RUNTIME_DIR}'
	TCL_NEEDS_EXP_FILE=1
	TCL_EXPORT_FILE_SUFFIX='${VERSION}\$\{DBGX\}.exp'
	;;
    BSD/OS-2.1*|BSD/OS-3*)
	SHLIB_CFLAGS=""
	SHLIB_LD="shlicc -r"
	SHLIB_LD_LIBS='${LIBS}'
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS="-ldl"
	LD_FLAGS=""
	LD_SEARCH_FLAGS=""
	;;
    BSD/OS-4.*)
	SHLIB_CFLAGS="-export-dynamic -fPIC"
	SHLIB_LD="cc -shared"
	SHLIB_LD_LIBS='${LIBS}'
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS="-ldl"
	LD_FLAGS="-export-dynamic"
	LD_SEARCH_FLAGS=""
	;;
    dgux*)
	SHLIB_CFLAGS="-K PIC"
	SHLIB_LD="cc -G"
	SHLIB_LD_LIBS=""
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS="-ldl"
	LD_FLAGS=""
	LD_SEARCH_FLAGS=""
	;;
    HP-UX-*.08.*|HP-UX-*.09.*|HP-UX-*.10.*|HP-UX-*.11.*)
	SHLIB_SUFFIX=".sl"
	AC_CHECK_LIB(dld, shl_load, tcl_ok=yes, tcl_ok=no)
	if test "$tcl_ok" = yes; then
	    SHLIB_CFLAGS="+z"
	    SHLIB_LD="ld -b"
	    SHLIB_LD_LIBS=""
	    DL_OBJS="tclLoadShl.o"
	    DL_LIBS="-ldld"
	    LD_FLAGS="-Wl,-E"
	    LD_SEARCH_FLAGS='-Wl,+s,+b,${LIB_RUNTIME_DIR}:.'
	fi
	;;
    IRIX-4.*)
	SHLIB_CFLAGS="-G 0"
	SHLIB_SUFFIX=".a"
	SHLIB_LD="echo tclLdAout $CC \{$SHLIB_CFLAGS\} | `pwd`/tclsh -r -G 0"
	SHLIB_LD_LIBS='${LIBS}'
	DL_OBJS="tclLoadAout.o"
	DL_LIBS=""
	LD_FLAGS="-Wl,-D,08000000"
	LD_SEARCH_FLAGS='-L${LIB_RUNTIME_DIR}'
	TCL_SHARED_LIB_SUFFIX='${VERSION}\$\{DBGX\}.a'
	;;
    IRIX-5.*|IRIX-6.*|IRIX64-6.5*)
	SHLIB_CFLAGS=""
	SHLIB_LD="ld -n32 -shared -rdata_shared"
	SHLIB_LD_LIBS=""
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS=""
	LD_SEARCH_FLAGS='-Wl,-rpath,${LIB_RUNTIME_DIR}'
	if test "$CC" = "gcc" -o `$CC -v 2>&1 | grep -c gcc` != "0" ; then
	    EXTRA_CFLAGS="-mabi=n32"
	    LD_FLAGS="-mabi=n32"
	else
	    case $system in
		IRIX-6.3)
		    # Use to build 6.2 compatible binaries on 6.3.
		    EXTRA_CFLAGS="-n32 -D_OLD_TERMIOS"
		    ;;
		*)
		    EXTRA_CFLAGS="-n32"
		    ;;
	    esac
	    LD_FLAGS="-n32"
	fi
	;;
    IRIX64-6.*)
	SHLIB_CFLAGS=""
	SHLIB_LD="ld -32 -shared -rdata_shared"
	SHLIB_LD_LIBS='${LIBS}'
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS=""
	LD_FLAGS=""
	LD_SEARCH_FLAGS='-Wl,-rpath,${LIB_RUNTIME_DIR}'
	;;
    Linux*)
	SHLIB_CFLAGS="-fPIC"
	SHLIB_LD_LIBS="${LIBS}"
	SHLIB_SUFFIX=".so"
	if test "$have_dl" = yes; then
	    SHLIB_LD="${CC} -shared"
	    DL_OBJS="tclLoadDl.o"
	    DL_LIBS="-ldl"
	    LD_FLAGS="-rdynamic"
	    LD_SEARCH_FLAGS='-Wl,-rpath,${LIB_RUNTIME_DIR}'
	else
	    AC_CHECK_HEADER(dld.h, [
		SHLIB_LD="ld -shared"
		DL_OBJS="tclLoadDld.o"
		DL_LIBS="-ldld"
		LD_FLAGS=""
		LD_SEARCH_FLAGS=""])
	fi
	;;
    MP-RAS-02*)
	SHLIB_CFLAGS="-K PIC"
	SHLIB_LD="cc -G"
	SHLIB_LD_LIBS=""
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS="-ldl"
	LD_FLAGS=""
	LD_SEARCH_FLAGS=""
	;;
    MP-RAS-*)
	SHLIB_CFLAGS="-K PIC"
	SHLIB_LD="cc -G"
	SHLIB_LD_LIBS=""
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS="-ldl"
	LD_FLAGS="-Wl,-Bexport"
	LD_SEARCH_FLAGS=""
	;;
    NetBSD-*|FreeBSD-[12].*|OpenBSD-*)
	# Not available on all versions:  check for include file.
	AC_CHECK_HEADER(dlfcn.h, [
	    SHLIB_CFLAGS="-fpic"
	    SHLIB_LD="ld -Bshareable -x"
	    SHLIB_LD_LIBS=""
	    SHLIB_SUFFIX=".so"
	    DL_OBJS="tclLoadDl.o"
	    DL_LIBS=""
	    LD_FLAGS=""
	    LD_SEARCH_FLAGS=""
	    TCL_SHARED_LIB_SUFFIX='${TCL_TRIM_DOTS}\$\{DBGX\}.so.1.0'
	], [
	    SHLIB_CFLAGS=""
	    SHLIB_LD="echo tclLdAout $CC \{$SHLIB_CFLAGS\} | `pwd`/tclsh -r"
	    SHLIB_LD_LIBS='${LIBS}'
	    SHLIB_SUFFIX=".a"
	    DL_OBJS="tclLoadAout.o"
	    DL_LIBS=""
	    LD_FLAGS=""
	    LD_SEARCH_FLAGS='-L${LIB_RUNTIME_DIR}'
	    TCL_SHARED_LIB_SUFFIX='${TCL_TRIM_DOTS}\$\{DBGX\}.a'
	])

	# FreeBSD doesn't handle version numbers with dots.

	TCL_UNSHARED_LIB_SUFFIX='${TCL_TRIM_DOTS}\$\{DBGX\}.a'
	TCL_LIB_VERSIONS_OK=nodots
        ;;
    FreeBSD-*)
        # FreeBSD 3.* and greater have ELF.
        SHLIB_CFLAGS="-fpic"
        SHLIB_LD="ld -Bshareable -x"
        SHLIB_LD_LIBS=""
        SHLIB_SUFFIX=".so"
        DL_OBJS="tclLoadDl.o"
        DL_LIBS=""
        LD_FLAGS=""
        LD_SEARCH_FLAGS=""
	;;
    NEXTSTEP-*)
	SHLIB_CFLAGS=""
	SHLIB_LD="cc -nostdlib -r"
	SHLIB_LD_LIBS=""
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadNext.o"
	DL_LIBS=""
	LD_FLAGS=""
	LD_SEARCH_FLAGS=""
	;;
    OSF1-1.0|OSF1-1.1|OSF1-1.2)
	# OSF/1 1.[012] from OSF, and derivatives, including Paragon OSF/1
	SHLIB_CFLAGS=""
	# Hack: make package name same as library name
	SHLIB_LD='ld -R -export $@:'
	SHLIB_LD_LIBS=""
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadOSF.o"
	DL_LIBS=""
	LD_FLAGS=""
	LD_SEARCH_FLAGS=""
	;;
    OSF1-1.*)
	# OSF/1 1.3 from OSF using ELF, and derivatives, including AD2
	SHLIB_CFLAGS="-fpic"
	SHLIB_LD="ld -shared"
	SHLIB_LD_LIBS=""
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS=""
	LD_FLAGS=""
	LD_SEARCH_FLAGS=""
	;;
    OSF1-V*)
        # Digital OSF/1
	SHLIB_CFLAGS=""
	SHLIB_LD='ld -shared -expect_unresolved "*"'
	SHLIB_LD_LIBS=""
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS=""
	LD_FLAGS=""
	LD_SEARCH_FLAGS='-Wl,-rpath,${LIB_RUNTIME_DIR}'
	;;
    RISCos-*)
	SHLIB_CFLAGS="-G 0"
	SHLIB_LD="echo tclLdAout $CC \{$SHLIB_CFLAGS\} | `pwd`/tclsh -r -G 0"
	SHLIB_LD_LIBS='${LIBS}'
	SHLIB_SUFFIX=".a"
	DL_OBJS="tclLoadAout.o"
	DL_LIBS=""
	LD_FLAGS="-Wl,-D,08000000"
	LD_SEARCH_FLAGS='-L${LIB_RUNTIME_DIR}'
	;;
    SCO_SV-3.2*)
        # Note, dlopen is available only on SCO 3.2.5 and greater.  However,
        # this test works, since "uname -s" was non-standard in 3.2.4 and
        # below.
	SHLIB_CFLAGS="-Kpic -belf"
	SHLIB_LD="ld -G"
	SHLIB_LD_LIBS=""
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS=""
	LD_FLAGS="-belf -Wl,-Bexport"
	LD_SEARCH_FLAGS=""
	;;
     SINIX*5.4*)
	SHLIB_CFLAGS="-K PIC"
	SHLIB_LD="cc -G"
	SHLIB_LD_LIBS=""
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS="-ldl"
	LD_FLAGS=""
	LD_SEARCH_FLAGS=""
	;;
    SunOS-4*)
	SHLIB_CFLAGS="-PIC"
	SHLIB_LD="ld"
	SHLIB_LD_LIBS=""
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS="-ldl"
	LD_FLAGS=""
	LD_SEARCH_FLAGS='-L${LIB_RUNTIME_DIR}'

	# SunOS can't handle version numbers with dots in them in library
	# specs, like -ltcl7.5, so use -ltcl75 instead.  Also, it
	# requires an extra version number at the end of .so file names.
	# So, the library has to have a name like libtcl75.so.1.0

	TCL_SHARED_LIB_SUFFIX='${TCL_TRIM_DOTS}\$\{DBGX\}.so.1.0'
	TCL_UNSHARED_LIB_SUFFIX='${TCL_TRIM_DOTS}\$\{DBGX\}.a'
	TCL_LIB_VERSIONS_OK=nodots
	;;
    SunOS-5.[[0-6]]*)
#    SunOS-5*)
	SHLIB_CFLAGS="-KPIC"
	SHLIB_LD="/usr/ccs/bin/ld -G -z text"

	# Note: need the LIBS below, otherwise Tk won't find Tcl's
	# symbols when dynamically loaded into tclsh.

	SHLIB_LD_LIBS='${LIBS}'
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS="-ldl"
	LD_FLAGS=""
	LD_SEARCH_FLAGS='-Wl,-R,${LIB_RUNTIME_DIR}'
	;;
    SunOS-5*)
	SHLIB_CFLAGS="-KPIC"
	SHLIB_LD="/usr/ccs/bin/ld -G -z text"
	LD_FLAGS=""
 
        do64bit_ok=no
	if test "$do64bit" = "yes" ; then
          arch=`isainfo`
          if test "$arch" = "sparcv9 sparc" ; then
	    if test "$CC" != "gcc" -a `$CC -v 2>&1 | grep -c gcc` = "0" ; then
    	      do64bit_ok=yes
              EXTRA_CFLAGS="-xarch=v9"
              LD_FLAGS="-xarch=v9"
	    else 
	      AC_MSG_WARN("64bit mode not supported using GCC on $system")
	    fi
          else
            AC_MSG_WARN("64bit mode only supported sparcv9 system")
          fi
	fi
        
        # Note: need the LIBS below, otherwise Tk won't find Tcl's
        # symbols when dynamically loaded into tclsh.

        SHLIB_LD_LIBS='${LIBS}'
        SHLIB_SUFFIX=".so"
        DL_OBJS="tclLoadDl.o"
        DL_LIBS="-ldl"
	if test "$CC" = "gcc" -o `$CC -v 2>&1 | grep -c gcc` != "0" ; then
	    LD_SEARCH_FLAGS='-Wl,-R,${LIB_RUNTIME_DIR}'
	else
	    LD_SEARCH_FLAGS='-R ${LIB_RUNTIME_DIR}'
	fi
        ;;
    ULTRIX-4.*)
	SHLIB_CFLAGS="-G 0"
	SHLIB_SUFFIX=".a"
	SHLIB_LD="echo tclLdAout $CC \{$SHLIB_CFLAGS\} | `pwd`/tclsh -r -G 0"
	SHLIB_LD_LIBS='${LIBS}'
	DL_OBJS="tclLoadAout.o"
	DL_LIBS=""
	LD_FLAGS="-Wl,-D,08000000"
	LD_SEARCH_FLAGS='-L${LIB_RUNTIME_DIR}'
	;;
    UNIX_SV* | UnixWare-5*)
	SHLIB_CFLAGS="-KPIC"
	SHLIB_LD="cc -G"
	SHLIB_LD_LIBS=""
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS="-ldl"
	# Some UNIX_SV* systems (unixware 1.1.2 for example) have linkers
	# that don't grok the -Bexport option.  Test that it does.
	hold_ldflags=$LDFLAGS
	AC_MSG_CHECKING(for ld accepts -Bexport flag)
	LDFLAGS="${LDFLAGS} -Wl,-Bexport"
	AC_TRY_LINK(, [int i;], found=yes, found=no)
	LDFLAGS=$hold_ldflags
	AC_MSG_RESULT($found)
	if test $found = yes; then
	  LD_FLAGS="-Wl,-Bexport"
	else
	  LD_FLAGS=""
	fi
	LD_SEARCH_FLAGS=""
	;;
esac

if test "$do64bit" = "yes" -a "$do64bit_ok" = "no" ; then
  AC_MSG_WARN("64bit support being disabled -- not supported on this platform")
fi

# Step 4: If pseudo-static linking is in use (see K. B. Kenny, "Dynamic
# Loading for Tcl -- What Became of It?".  Proc. 2nd Tcl/Tk Workshop,
# New Orleans, LA, Computerized Processes Unlimited, 1994), then we need
# to determine which of several header files defines the a.out file
# format (a.out.h, sys/exec.h, or sys/exec_aout.h).  At present, we
# support only a file format that is more or less version-7-compatible. 
# In particular,
#	- a.out files must begin with `struct exec'.
#	- the N_TXTOFF on the `struct exec' must compute the seek address
#	  of the text segment
#	- The `struct exec' must contain a_magic, a_text, a_data, a_bss
#	  and a_entry fields.
# The following compilation should succeed if and only if either sys/exec.h
# or a.out.h is usable for the purpose.
#
# Note that the modified COFF format used on MIPS Ultrix 4.x is usable; the
# `struct exec' includes a second header that contains information that
# duplicates the v7 fields that are needed.

if test "x$DL_OBJS" = "xtclLoadAout.o" ; then
    AC_MSG_CHECKING(sys/exec.h)
    AC_TRY_COMPILE([#include <sys/exec.h>],[
	struct exec foo;
	unsigned long seek;
	int flag;
#if defined(__mips) || defined(mips)
	seek = N_TXTOFF (foo.ex_f, foo.ex_o);
#else
	seek = N_TXTOFF (foo);
#endif
	flag = (foo.a_magic == OMAGIC);
	return foo.a_text + foo.a_data + foo.a_bss + foo.a_entry;
], tcl_ok=usable, tcl_ok=unusable)
    AC_MSG_RESULT($tcl_ok)
    if test $tcl_ok = usable; then
	AC_DEFINE(USE_SYS_EXEC_H)
    else
	AC_MSG_CHECKING(a.out.h)
	AC_TRY_COMPILE([#include <a.out.h>],[
	    struct exec foo;
	    unsigned long seek;
	    int flag;
#if defined(__mips) || defined(mips)
	    seek = N_TXTOFF (foo.ex_f, foo.ex_o);
#else
	    seek = N_TXTOFF (foo);
#endif
	    flag = (foo.a_magic == OMAGIC);
	    return foo.a_text + foo.a_data + foo.a_bss + foo.a_entry;
	], tcl_ok=usable, tcl_ok=unusable)
	AC_MSG_RESULT($tcl_ok)
	if test $tcl_ok = usable; then
	    AC_DEFINE(USE_A_OUT_H)
	else
	    AC_MSG_CHECKING(sys/exec_aout.h)
	    AC_TRY_COMPILE([#include <sys/exec_aout.h>],[
		struct exec foo;
		unsigned long seek;
		int flag;
#if defined(__mips) || defined(mips)
		seek = N_TXTOFF (foo.ex_f, foo.ex_o);
#else
		seek = N_TXTOFF (foo);
#endif
		flag = (foo.a_midmag == OMAGIC);
		return foo.a_text + foo.a_data + foo.a_bss + foo.a_entry;
	    ], tcl_ok=usable, tcl_ok=unusable)
	    AC_MSG_RESULT($tcl_ok)
	    if test $tcl_ok = usable; then
		AC_DEFINE(USE_SYS_EXEC_AOUT_H)
	    else
		DL_OBJS=""
	    fi
	fi
    fi
fi

# Step 5: disable dynamic loading if requested via a command-line switch.

AC_ARG_ENABLE(load, [  --disable-load          disallow dynamic loading and "load" command],
    [tcl_ok=$enableval], [tcl_ok=yes])
if test "$tcl_ok" = "no"; then
    DL_OBJS=""
fi

if test "x$DL_OBJS" != "x" ; then
    BUILD_DLTEST="\$(DLTEST_TARGETS)"
else
    echo "Can't figure out how to do dynamic loading or shared libraries"
    echo "on this system."
    SHLIB_CFLAGS=""
    SHLIB_LD=""
    SHLIB_SUFFIX=""
    DL_OBJS="tclLoadNone.o"
    DL_LIBS=""
    LD_FLAGS=""
    LD_SEARCH_FLAGS=""
    BUILD_DLTEST=""
fi

# If we're running gcc, then change the C flags for compiling shared
# libraries to the right flags for gcc, instead of those for the
# standard manufacturer compiler.

if test "$DL_OBJS" != "tclLoadNone.o" ; then
    if test "$CC" = "gcc" -o `$CC -v 2>&1 | grep -c gcc` != "0" ; then
	case $system in
	    AIX-*)
		;;
	    BSD/OS*)
		;;
	    IRIX*)
		;;
	    NetBSD-*|FreeBSD-*|OpenBSD-*)
		;;
	    RISCos-*)
		;;
	    ULTRIX-4.*)
		;;
	    *)
		SHLIB_CFLAGS="-fPIC"
		;;
	esac
    fi
fi

# Set the default compiler switches based on the --enable-symbols option 

AC_ARG_ENABLE(symbols, [  --enable-symbols        build with debugging symbols],
    [tcl_ok=$enableval], [tcl_ok=no])
if test "$tcl_ok" = "yes"; then
    CFLAGS='$(CFLAGS_DEBUG)'
    TCL_DBGX=g
else
    CFLAGS='$(CFLAGS_OPTIMIZE)'
    TCL_DBGX=""
fi

#--------------------------------------------------------------------
#	The statements below check for systems where POSIX-style
#	non-blocking I/O (O_NONBLOCK) doesn't work or is unimplemented. 
#	On these systems (mostly older ones), use the old BSD-style
#	FIONBIO approach instead.
#--------------------------------------------------------------------

AC_CHECK_HEADERS(sys/ioctl.h)
AC_CHECK_HEADERS(sys/filio.h)
AC_MSG_CHECKING([FIONBIO vs. O_NONBLOCK for nonblocking I/O])
if test -f /usr/lib/NextStep/software_version; then
    system=NEXTSTEP-`awk '/3/,/3/' /usr/lib/NextStep/software_version`
else
    system=`uname -s`-`uname -r`
    if test "$?" -ne 0 ; then
	system=unknown
    else
	# Special check for weird MP-RAS system (uname returns weird
	# results, and the version is kept in special file).
    
	if test -r /etc/.relid -a "X`uname -n`" = "X`uname -s`" ; then
	    system=MP-RAS-`awk '{print $3}' /etc/.relid'`
	fi
	if test "`uname -s`" = "AIX" ; then
	    system=AIX-`uname -v`.`uname -r`
	fi
    fi
fi
case $system in
    # There used to be code here to use FIONBIO under AIX.  However, it
    # was reported that FIONBIO doesn't work under AIX 3.2.5.  Since
    # using O_NONBLOCK seems fine under AIX 4.*, I removed the FIONBIO
    # code (JO, 5/31/97).

    OSF*)
	AC_DEFINE(USE_FIONBIO)
	AC_MSG_RESULT(FIONBIO)
	;;
    SunOS-4*)
	AC_DEFINE(USE_FIONBIO)
	AC_MSG_RESULT(FIONBIO)
	;;
    ULTRIX-4.*)
	AC_DEFINE(USE_FIONBIO)
	AC_MSG_RESULT(FIONBIO)
	;;
    *)
	AC_MSG_RESULT(O_NONBLOCK)
	;;
esac

#--------------------------------------------------------------------
#	The statements below define a collection of symbols related to
#	building libtcl as a shared library instead of a static library.
#--------------------------------------------------------------------

realRanlib=$RANLIB
if test "$TCL_SHARED_LIB_SUFFIX" = "" ; then
    TCL_SHARED_LIB_SUFFIX='${VERSION}\$\{DBGX\}${SHLIB_SUFFIX}'
fi
if test "$TCL_UNSHARED_LIB_SUFFIX" = "" ; then
    TCL_UNSHARED_LIB_SUFFIX='${VERSION}\$\{DBGX\}.a'
fi
AC_ARG_ENABLE(shared,
    [  --enable-shared         build libtcl as a shared library (on by default)],
    [tcl_ok=$enableval], [tcl_ok=yes])
if test "$tcl_ok" = "yes" -a "${SHLIB_SUFFIX}" != "" ; then
    TCL_SHARED_BUILD=1
    TCL_SHLIB_CFLAGS="${SHLIB_CFLAGS}"
    TCL_LD_SEARCH_FLAGS="${LD_SEARCH_FLAGS}"
    eval "TCL_LIB_FILE=libtcl${TCL_SHARED_LIB_SUFFIX}"
    if test "x$DL_OBJS" = "xtclLoadAout.o"; then
	MAKE_LIB="ar cr \${TCL_LIB_FILE} \${OBJS}"
    else
	MAKE_LIB="\${SHLIB_LD} -o \${TCL_LIB_FILE} \${OBJS} ${SHLIB_LD_LIBS}"
	RANLIB=":"
    fi
else
    TCL_SHARED_BUILD=0
    case $system in
        BSD/OS*)
	    ;;

	AIX-*)
            ;;

        *)
	    SHLIB_LD_LIBS=""
	    ;;
    esac
    TCL_SHLIB_CFLAGS=""
    TCL_LD_SEARCH_FLAGS="${LD_SEARCH_FLAGS}"
    eval "TCL_LIB_FILE=libtcl${TCL_UNSHARED_LIB_SUFFIX}"
    MAKE_LIB="ar cr \${TCL_LIB_FILE} \${OBJS}"
fi

# tclConfig.sh needs a version of the _LIB_SUFFIX that has been eval'ed
# so that the backslashes quoting the DBX braces are dropped.

# Trick to replace DBGX with TCL_DBGX
DBGX='${TCL_DBGX}'
eval "TCL_LIB_FILE=${TCL_LIB_FILE}"

# Note:  in the following variable, it's important to use the absolute
# path name of the Tcl directory rather than "..":  this is because
# AIX remembers this path and will attempt to use it at run-time to look
# up the Tcl library.

if test $TCL_SHARED_BUILD = 0 -o $TCL_NEEDS_EXP_FILE = 0; then
    if test "${TCL_LIB_VERSIONS_OK}" = "ok"; then
        TCL_LIB_FLAG="-ltcl${TCL_VERSION}\${TCL_DBGX}"
    else
        TCL_LIB_FLAG="-ltcl`echo ${TCL_VERSION} | tr -d .`\${TCL_DBGX}"
    fi
    TCL_BUILD_LIB_SPEC="-L`pwd` ${TCL_LIB_FLAG}"
    TCL_LIB_SPEC="-L${exec_prefix}/lib ${TCL_LIB_FLAG}"
else
    TCL_BUILD_EXP_FILE="lib.exp"
    eval "TCL_EXP_FILE=libtcl${TCL_EXPORT_FILE_SUFFIX}"

    # Replace DBGX with TCL_DBGX
    eval "TCL_EXP_FILE=\"${TCL_EXP_FILE}\""
    
    TCL_BUILD_LIB_SPEC="-bI:`pwd`/${TCL_BUILD_EXP_FILE}"
    TCL_LIB_SPEC="-bI:${exec_prefix}/lib/${TCL_EXP_FILE}"    
fi
VERSION='${VERSION}'
eval "CFG_TCL_SHARED_LIB_SUFFIX=${TCL_SHARED_LIB_SUFFIX}"
eval "CFG_TCL_UNSHARED_LIB_SUFFIX=${TCL_UNSHARED_LIB_SUFFIX}"
eval "CFG_TCL_EXPORT_FILE_SUFFIX=${TCL_EXPORT_FILE_SUFFIX}"
VERSION=${TCL_VERSION}

#--------------------------------------------------------------------
#	The statements below define the symbol TCL_PACKAGE_PATH, which
#	gives a list of directories that may contain packages.  The list
#	consists of one directory for machine-dependent binaries and
#	another for platform-independent scripts.
#--------------------------------------------------------------------

if test "$prefix" != "$exec_prefix"; then
    TCL_PACKAGE_PATH="${exec_prefix}/lib ${prefix}/lib"
else
    TCL_PACKAGE_PATH="${prefix}/lib"
fi

#--------------------------------------------------------------------
#       The statements below define various symbols relating to Tcl
#       stub support.
#--------------------------------------------------------------------
# Replace ${VERSION} with contents of ${TCL_VERSION}
eval "STUB_LIB_FILE=libtclstub${TCL_UNSHARED_LIB_SUFFIX}"
# Replace DBGX with TCL_DBGX
eval "STUB_LIB_FILE=\"${STUB_LIB_FILE}\""

MAKE_STUB_LIB="ar cr \${STUB_LIB_FILE} \${STUB_LIB_OBJS}"

TCL_STUB_LIB_FILE=${STUB_LIB_FILE}

if test "${TCL_LIB_VERSIONS_OK}" = "ok"; then
    TCL_STUB_LIB_FLAG="-ltclstub${TCL_VERSION}\${TCL_DBGX}"
else
    TCL_STUB_LIB_FLAG="-ltclstub`echo ${TCL_VERSION} | tr -d .`\${TCL_DBGX}"
fi

TCL_BUILD_STUB_LIB_SPEC="-L`pwd` ${TCL_STUB_LIB_FLAG}"
TCL_STUB_LIB_SPEC="-L${exec_prefix}/lib ${TCL_STUB_LIB_FLAG}"
TCL_BUILD_STUB_LIB_PATH="`pwd`/${TCL_STUB_LIB_FILE}"
TCL_STUB_LIB_PATH="${exec_prefix}/lib/${TCL_STUB_LIB_FILE}"

AC_SUBST(STUB_LIB_FILE)

AC_SUBST(TCL_STUB_LIB_FILE)
AC_SUBST(TCL_STUB_LIB_FLAG)
AC_SUBST(TCL_BUILD_STUB_LIB_SPEC)
AC_SUBST(TCL_STUB_LIB_SPEC)
AC_SUBST(TCL_BUILD_STUB_LIB_PATH)
AC_SUBST(TCL_STUB_LIB_PATH)
AC_SUBST(MAKE_STUB_LIB)

AC_SUBST(BUILD_DLTEST)
AC_SUBST(CFLAGS)
AC_SUBST(CFLAGS_DEBUG)
AC_SUBST(CFLAGS_OPTIMIZE)
AC_SUBST(CFLAGS_WARNING)
AC_SUBST(CFG_TCL_SHARED_LIB_SUFFIX)
AC_SUBST(CFG_TCL_UNSHARED_LIB_SUFFIX)
AC_SUBST(CFG_TCL_EXPORT_FILE_SUFFIX)
AC_SUBST(TCL_DBGX)
AC_SUBST(DL_LIBS)
AC_SUBST(DL_OBJS)
AC_SUBST(EXTRA_CFLAGS)
AC_SUBST(LD_FLAGS)
AC_SUBST(MAKE_LIB)
AC_SUBST(MATH_LIBS)
AC_SUBST(SHLIB_CFLAGS)
AC_SUBST(SHLIB_LD)
AC_SUBST(SHLIB_LD_LIBS)
AC_SUBST(SHLIB_SUFFIX)
AC_SUBST(TCL_BUILD_LIB_SPEC)
AC_SUBST(TCL_LD_SEARCH_FLAGS)
AC_SUBST(TCL_LIB_FILE)
AC_SUBST(TCL_LIB_FLAG)
AC_SUBST(TCL_NEEDS_EXP_FILE)
AC_SUBST(TCL_BUILD_EXP_FILE)
AC_SUBST(TCL_EXP_FILE)
AC_SUBST(TCL_LIB_SPEC)
AC_SUBST(TCL_LIB_VERSIONS_OK)
AC_SUBST(TCL_MAJOR_VERSION)
AC_SUBST(TCL_MINOR_VERSION)
AC_SUBST(TCL_PACKAGE_PATH)
AC_SUBST(TCL_PATCH_LEVEL)
AC_SUBST(TCL_SHARED_LIB_SUFFIX)
AC_SUBST(TCL_SHARED_BUILD)
AC_SUBST(TCL_SHLIB_CFLAGS)
AC_SUBST(TCL_SRC_DIR)
AC_SUBST(TCL_UNSHARED_LIB_SUFFIX)
AC_SUBST(TCL_VERSION)

AC_OUTPUT(Makefile tclConfig.sh)