dnl ===========================================================================
dnl Additional macros used to configure GiNaC.  We don't start our own 
dnl additions' names with AC_ but with GINAC_ in order to steer clear of
dnl future trouble.
dnl ===========================================================================

dnl Generally, it is a bad idea to put specialized header files for a library
dnl into a generic directory like /usr/local/include/.  Instead, one should put
dnl them into a subdirectory.  GiNaC does it, NTL does it.  Unfortunately, CLN
dnl doesn't do so but some people choose to do it by hand.  In these cases we
dnl need to #include <cln/cln.h>, otherwise #include <cln.h>.  This macro
dnl tries to be clever and find out the correct way by defining the variable
dnl HAVE_CLN_CLN_H in config.h:
AC_DEFUN(GINAC_CHECK_CLN_H,
    [AC_PROVIDE([$0])
    AC_CHECK_HEADERS(cln/cln.h, ,
        AC_CHECK_HEADERS(cln.h, ,
            AC_MSG_ERROR([cannot find header for Bruno Haible's CLN]);
        )
    )
])

dnl This macro is needed because the generic AC_CHECK_LIB doesn't work because
dnl C++ is more strongly typed than C.  Therefore we need to work with the 
dnl more fundamental AC_TRY_LINK instead.
AC_DEFUN(GINAC_CHECK_LIBCLN,
    [AC_PROVIDE([$0])
    AC_MSG_CHECKING([for doublefactorial in -lcln])
    saved_LIBS="${LIBS}"
    AC_CACHE_VAL(ginac_cv_lib_cln_link,
        [LIBS="-lcln"
        case "${ac_cv_header_cln_cln_h}" in
        "yes")
            AC_TRY_LINK([#include <cln/cl_integer.h>],
                [doublefactorial(2);],
                ginac_cv_lib_cln_link="-lcln",
                ginac_cv_lib_cln_link="fail")
            ;;
        *)
            AC_TRY_LINK([#include <cl_integer.h>],
                [doublefactorial(2);],
                ginac_cv_lib_cln_link="-lcln",
                ginac_cv_lib_cln_link="fail")
            ;;
        esac
    ])
    case "${ginac_cv_lib_cln_link}" in
dnl linking worked:
    "-lcln")
        LIBS="${ginac_cv_lib_cln_link} ${saved_LIBS}"
        AC_MSG_RESULT("yes")
    ;;
dnl linking failed:
    "fail")
        LIBS="${saved_LIBS}"
        AC_MSG_RESULT([no])
        GINAC_ERROR([I could not successfully link a test-program against libcln and run it.
   You either need to set \$LDFLAGS or install/update the CLN library.])
    ;;
    esac
])

dnl Usage: GINAC_TERMCAP
dnl libreadline is based on the termcap functions.
dnl Some systems have tgetent(), tgetnum(), tgetstr(), tgetflag(), tputs(),
dnl tgoto() in libc, some have it in libtermcap, some have it in libncurses.
dnl When both libtermcap and libncurses exist, we prefer the latter, because
dnl libtermcap is being phased out.
AC_DEFUN(GINAC_TERMCAP,
[LIBTERMCAP=
AC_CHECK_FUNCS(tgetent)
if test "x$ac_cv_func_tgetent" = "xyes"; then
    :
else
    AC_CHECK_LIB(ncurses, tgetent, LIBTERMCAP="-lncurses")
    if test -z "$LIBTERMCAP"; then
        AC_CHECK_LIB(termcap, tgetent, LIBTERMCAP="-ltermcap")
    fi
fi
AC_SUBST(LIBTERMCAP)
])

dnl Usage: GINAC_ERROR(message)
dnl This macro displays the warning "message" and sets the flag ginac_error
dnl to yes.
AC_DEFUN(GINAC_ERROR,[
ginac_error_txt="$ginac_error_txt
** $1
"
ginac_error=yes])

dnl Usage: GINAC_WARNING(message)
dnl This macro displays the warning "message" and sets the flag ginac_warning
dnl to yes.
AC_DEFUN(GINAC_WARNING,[
ginac_warning_txt="$ginac_warning_txt
== $1
"
ginac_warning=yes])

dnl Usage: GINAC_CHECK_ERRORS
dnl (preferably to be put at end of configure.in)
dnl This macro displays a warning message if GINAC_ERROR or GINAC_WARNING 
dnl has occured previously.
AC_DEFUN(GINAC_CHECK_ERRORS,[
if test "x${ginac_error}" = "xyes"; then
    echo "**** The following problems have been detected by configure."
    echo "**** Please check the messages below before running \"make\"."
    echo "**** (see the section 'Common Problems' in the INSTALL file)"
    echo "$ginac_error_txt"
    if test "x${ginac_warning_txt}" != "x"; then
        echo "${ginac_warning_txt}"
    fi
    echo "deleting cache ${cache_file}"
    rm -f $cache_file
    else 
        if test x$ginac_warning = xyes; then
            echo "=== The following minor problems have been detected by configure."
            echo "=== Please check the messages below before running \"make\"."
            echo "=== (see the section 'Common Problems' in the INSTALL file)"
            echo "$ginac_warning_txt"
        fi
    echo "Configuration of GiNaC $VERSION done. Now type \"make\"."
fi])