dnl @synopsis AC_JNI_INCLUDE_DIR
dnl
dnl AC_JNI_INCLUDE_DIR finds include directories needed
dnl for compiling programs using the JNI interface.
dnl
dnl JNI include directories are usually in the java distribution
dnl This is deduced from the value of JAVAC.  When this macro
dnl completes, a list of directories is left in the variable
dnl JNI_INCLUDE_DIRS.
dnl
dnl Example usage follows:
dnl
dnl     AC_JNI_INCLUDE_DIR
dnl
dnl     for JNI_INCLUDE_DIR in $JNI_INCLUDE_DIRS
dnl     do
dnl             CPPFLAGS="$CPPFLAGS -I$JNI_INCLUDE_DIR"
dnl     done
dnl
dnl If you want to force a specific compiler:
dnl
dnl - at the configure.in level, set JAVAC=yourcompiler before calling
dnl AC_JNI_INCLUDE_DIR
dnl
dnl - at the configure level, setenv JAVAC
dnl
dnl Note: This macro can work with the autoconf M4 macros for Java programs.
dnl This particular macro is not part of the original set of macros.
dnl
dnl @author Don Anderson <dda@sleepycat.com>
dnl @version $Id: ac_jni_include_dirs.m4,v 1.1 2001/09/25 01:25 ac-archive-0.5.39 $
dnl
AC_DEFUN(AC_JNI_INCLUDE_DIR,[

JNI_INCLUDE_DIRS=""

test "x$JAVAC" = x && AC_MSG_ERROR(['$JAVAC' undefined])
AC_PATH_PROG(_ACJNI_JAVAC, $JAVAC, no)
test "x$_ACJNI_JAVAC" = xno && AC_MSG_ERROR([$JAVAC could not be found in path])

_ACJNI_FOLLOW_SYMLINKS("$_ACJNI_JAVAC")
_JTOPDIR=`echo "$_ACJNI_FOLLOWED" | sed -e 's://*:/:g' -e 's:/[[^/]]*$::'`
case "$host_os" in
        darwin*)        _JTOPDIR=`echo "$_JTOPDIR" | sed -e 's:/[[^/]]*$::'`
                        _JINC="$_JTOPDIR/Headers";;
        *)              _JINC="$_JTOPDIR/include";;
esac
if test -f "$_JINC/jni.h"; then
        JNI_INCLUDE_DIRS="$JNI_INCLUDE_DIRS $_JINC"
else
        _JTOPDIR=`echo "$_JTOPDIR" | sed -e 's:/[[^/]]*$::'`
        if test -f "$_JTOPDIR/include/jni.h"; then
                JNI_INCLUDE_DIRS="$JNI_INCLUDE_DIRS $_JTOPDIR/include"
        else
                AC_MSG_ERROR([cannot find java include files])
        fi
fi

# get the likely subdirectories for system specific java includes
case "$host_os" in
bsdi*)          _JNI_INC_SUBDIRS="bsdos";;
linux*)         _JNI_INC_SUBDIRS="linux genunix";;
osf*)           _JNI_INC_SUBDIRS="alpha";;
solaris*)       _JNI_INC_SUBDIRS="solaris";;
*)              _JNI_INC_SUBDIRS="genunix";;
esac

# add any subdirectories that are present
for JINCSUBDIR in $_JNI_INC_SUBDIRS
do
        if test -d "$_JTOPDIR/include/$JINCSUBDIR"; then
                JNI_INCLUDE_DIRS="$JNI_INCLUDE_DIRS $_JTOPDIR/include/$JINCSUBDIR"
        fi
done
])

# _ACJNI_FOLLOW_SYMLINKS <path>
# Follows symbolic links on <path>,
# finally setting variable _ACJNI_FOLLOWED
# --------------------
AC_DEFUN(_ACJNI_FOLLOW_SYMLINKS,[
# find the include directory relative to the javac executable
_cur="$1"
while ls -ld "$_cur" 2>/dev/null | grep " -> " >/dev/null; do
        AC_MSG_CHECKING(symlink for $_cur)
        _slink=`ls -ld "$_cur" | sed 's/.* -> //'`
        case "$_slink" in
        /*) _cur="$_slink";;
        # 'X' avoids triggering unwanted echo options.
        *) _cur=`echo "X$_cur" | sed -e 's/^X//' -e 's:[[^/]]*$::'`"$_slink";;
        esac
        AC_MSG_RESULT($_cur)
done
_ACJNI_FOLLOWED="$_cur"
])# _ACJNI