path: root/contrib/tcl/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)
# SCCS: @(#) configure.in 1.102 96/04/17 10:46:25

TCL_VERSION=7.5
TCL_MAJOR_VERSION=7
TCL_MINOR_VERSION=5
VERSION=${TCL_VERSION}

if test "${prefix}" = "NONE"; then
    prefix=/usr/local
fi
if test "${exec_prefix}" = "NONE"; then
    exec_prefix=$prefix
fi

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

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

AC_REPLACE_FUNCS(getcwd 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))

#--------------------------------------------------------------------
#	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"])

#--------------------------------------------------------------------
#	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(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)
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_HAVE_HEADERS(unistd.h)

#--------------------------------------------------------------------
#	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.
#
AC_MSG_CHECKING([timezone variable])
AC_TRY_COMPILE([#include <time.h>],
        [extern long timezone;
         timezone += 1;
         exit (0);],
        [AC_DEFINE(HAVE_TIMEZONE_VAR)
         AC_MSG_RESULT(yes)],
        AC_MSG_RESULT(no))

#--------------------------------------------------------------------
#	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_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))

#--------------------------------------------------------------------
#	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"]))

#--------------------------------------------------------------------
#	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_INSTALL_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 libtcl7.5.so or libtcl7.5.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}.
#--------------------------------------------------------------------

# 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: 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
    system=unknown
fi

# Step 4: set configuration options based on system name and version.

fullSrcDir=`cd $srcdir; pwd`
AIX=no
TCL_SHARED_LIB_SUFFIX=""
TCL_UNSHARED_LIB_SUFFIX=""
TCL_LIB_VERSIONS_OK=ok
case $system in
    AIX-*)
	SHLIB_CFLAGS=""
	SHLIB_LD="$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_INSTALL_DIR}'
	AC_DEFINE(NO_DLFCN_H)
	AIX=yes
	TCL_SHARED_LIB_SUFFIX='${VERSION}.a'
	;;
    HP-UX-*.08.*|HP-UX-*.09.*|HP-UX-*.10.*)
	SHLIB_CFLAGS="+z"
	SHLIB_LD="ld -b"
	SHLIB_LD_LIBS='${LIBS}'
	SHLIB_SUFFIX=".sl"
	DL_OBJS="tclLoadShl.o"
	DL_LIBS="-ldld"
	LD_FLAGS="-Wl,-E"
	LD_SEARCH_FLAGS='-Wl,+b,${LIB_INSTALL_DIR}:.'
	;;
    IRIX-4.*)
	SHLIB_CFLAGS="-G 0"
	SHLIB_SUFFIX="..o"
	SHLIB_LD="echo tclLdAout $CC \{$SHLIB_CFLAGS\} | `pwd`/tclsh -r -G 0"
	SHLIB_LD_LIBS=""
	DL_OBJS="tclLoadAout.o"
	DL_LIBS=""
	LD_FLAGS="-Wl,-D,08000000"
	LD_SEARCH_FLAGS=""
	;;
    IRIX-5.*)
	SHLIB_CFLAGS=""
	SHLIB_LD="ld -shared -rdata_shared"
	SHLIB_LD_LIBS=""
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS=""
	LD_FLAGS=""
	LD_SEARCH_FLAGS='-Wl,-rpath,${LIB_INSTALL_DIR}'
	;;
    Linux*)
	SHLIB_CFLAGS="-fPIC"
	SHLIB_LD_LIBS=""
	SHLIB_SUFFIX=".so"
	if test "$have_dl" = yes; then
	    SHLIB_LD="${CC} -shared"
	    DL_OBJS="tclLoadDl.o"
	    DL_LIBS="-ldl"
	    LD_FLAGS="-rdynamic"
	    LD_SEARCH_FLAGS=""
	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-*)
	# Not available on all versions:  check for include file.
	AC_CHECK_HEADER(dlfcn.h, [
	    SHLIB_CFLAGS="-fpic"
	    SHLIB_LD="ld -Bshareable"
	    SHLIB_LD_LIBS=""
	    SHLIB_SUFFIX=".so"
	    DL_OBJS="tclLoadDl2.o"
	    DL_LIBS=""
	    LD_FLAGS=""
	    LD_SEARCH_FLAGS=""
	], [
	    SHLIB_CFLAGS=""
	    SHLIB_LD="echo tclLdAout $CC \{$SHLIB_CFLAGS\} | `pwd`/tclsh -r -G 0"
	    SHLIB_LD_LIBS=""
	    SHLIB_SUFFIX="..o"
	    DL_OBJS="tclLoadAout.o"
	    DL_LIBS=""
	    LD_FLAGS=""
	    LD_SEARCH_FLAGS=""
	])

	# FreeBSD doesn't handle version numbers with dots.  Also, have to
	# append a dummy version number to .so file names.

	TCL_SHARED_LIB_SUFFIX='`echo ${VERSION} | tr -d .`.so.1.0'
	TCL_UNSHARED_LIB_SUFFIX='`echo ${VERSION} | tr -d .`.a'
	TCL_LIB_VERSIONS_OK=nodots
	;;
    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.[012])
	# 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_INSTALL_DIR}'
	;;
    RISCos-*)
	SHLIB_CFLAGS="-G 0"
	SHLIB_LD="echo tclLdAout $CC \{$SHLIB_CFLAGS\} | `pwd`/tclsh -r -G 0"
	SHLIB_LD_LIBS=""
	SHLIB_SUFFIX="..o"
	DL_OBJS="tclLoadAout.o"
	DL_LIBS=""
	LD_FLAGS="-Wl,-D,08000000"
	LD_SEARCH_FLAGS=""
	;;
    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_INSTALL_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='`echo ${VERSION} | tr -d .`.so.1.0'
	TCL_UNSHARED_LIB_SUFFIX='`echo ${VERSION} | tr -d .`.a'
	TCL_LIB_VERSIONS_OK=nodots
	;;
    SunOS-5*)
	SHLIB_CFLAGS="-K PIC"
	SHLIB_LD="/usr/ccs/bin/ld -G -z text"
	SHLIB_LD_LIBS='${LIBS}'
	SHLIB_SUFFIX=".so"
	DL_OBJS="tclLoadDl.o"
	DL_LIBS="-ldl"
	LD_FLAGS=""
	LD_SEARCH_FLAGS='-R ${LIB_INSTALL_DIR}'
	;;
    ULTRIX-4.*)
	SHLIB_CFLAGS="-G 0"
	SHLIB_SUFFIX="..o"
	SHLIB_LD="echo tclLdAout $CC \{$SHLIB_CFLAGS\} | `pwd`/tclsh -r -G 0"
	SHLIB_LD_LIBS=""
	DL_OBJS="tclLoadAout.o"
	DL_LIBS=""
	LD_FLAGS="-Wl,-D,08000000"
	LD_SEARCH_FLAGS=""
	;;
    UNIX_SV*)
	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=""
	;;
esac

# 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

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
	SHLIB_CFLAGS="-fPIC"
    fi
fi

#--------------------------------------------------------------------
#	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='${VERSION}${SHLIB_SUFFIX}'
fi
if test "$TCL_UNSHARED_LIB_SUFFIX" = "" ; then
    TCL_UNSHARED_LIB_SUFFIX='${VERSION}.a'
fi
AC_ARG_ENABLE(shared,
    [  --enable-shared         build libtcl as a shared library],
    [tcl_ok=$enableval], [tcl_ok=no])
if test "$tcl_ok" = "yes" -a "${SHLIB_SUFFIX}" != "" \
	-a "${DL_OBJS}" != "tclLoadAout.o" ; then
    TCL_SHLIB_CFLAGS="${SHLIB_CFLAGS}"
    TCL_LD_SEARCH_FLAGS="${LD_SEARCH_FLAGS}"
    eval "TCL_LIB_FILE=libtcl${TCL_SHARED_LIB_SUFFIX}"
    MAKE_LIB="\${SHLIB_LD} -o ${TCL_LIB_FILE} \${OBJS} ${SHLIB_LD_LIBS}"
    RANLIB=":"
else
    if test "$AIX" = "no" ; then
	SHLIB_LD_LIBS=""
    fi
    TCL_SHLIB_CFLAGS=""
    TCL_LD_SEARCH_FLAGS=""
    eval "TCL_LIB_FILE=libtcl${TCL_UNSHARED_LIB_SUFFIX}"
    MAKE_LIB="ar cr ${TCL_LIB_FILE} \${OBJS}"
fi

# 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 "${TCL_LIB_VERSIONS_OK}" = "ok"; then
    TCL_BUILD_LIB_SPEC="-L`pwd` -ltcl${VERSION}"
    TCL_LIB_SPEC="-L${exec_prefix}/lib -ltcl${VERSION}"
else
    TCL_BUILD_LIB_SPEC="-L`pwd` -ltcl`echo ${VERSION} | tr -d .`"
    TCL_LIB_SPEC="-L${exec_prefix}/lib -ltcl`echo ${VERSION} | tr -d .`"
fi

AC_SUBST(BUILD_DLTEST)
AC_SUBST(DL_LIBS)
AC_SUBST(DL_OBJS)
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_SPEC)
AC_SUBST(TCL_LIB_VERSIONS_OK)
AC_SUBST(TCL_MAJOR_VERSION)
AC_SUBST(TCL_MINOR_VERSION)
AC_SUBST(TCL_SHARED_LIB_SUFFIX)
AC_SUBST(TCL_SHLIB_CFLAGS)
AC_SUBST(TCL_UNSHARED_LIB_SUFFIX)
AC_SUBST(TCL_VERSION)

AC_OUTPUT(Makefile tclConfig.sh)