+# This macro expands DIR and assigns it to RET.
+# If DIR is NONE, then it's replaced by DEFAULT.
+#
+# Based on AC_DEFINE_DIR
+#
+# Examples:
+#
+# AC_EXPAND(prefix, "/usr/local", expanded_prefix)
+
+AC_DEFUN([AC_EXPAND], [
+ test "x$prefix" = xNONE && prefix="$ac_default_prefix"
+ test "x$exec_prefix" = xNONE && exec_prefix='${prefix}'
+ ac_expand=[$]$1
+ test "x$ac_expand" = xNONE && ac_expand="[$]$2"
+ ac_expand=`eval echo [$]ac_expand`
+ $3=`eval echo [$]ac_expand`
+])
+
+# adl_NORMALIZE_PATH
+#
+# - empty paths are changed to '.'
+# - trailing slashes are removed
+# - repeated slashes are squeezed except a leading doubled slash '//'
+# (which might indicate a networked disk on some OS).
+#
+#
+# REFERENCE_STRING is used to turn '/' into '\' and vice-versa: if
+# REFERENCE_STRING contains some backslashes, all slashes and backslashes
+# are turned into backslashes, otherwise they are all turned into slashes.
+#
+# This makes processing of DOS filenames quite easier, because you can turn a
+# filename to the Unix notation, make your processing, and turn it back to
+# original notation.
+
+dnl Available from the GNU Autoconf Macro Archive at:
+dnl http://www.gnu.org/software/ac-archive/htmldoc/normpath.html
+dnl
+AC_DEFUN([adl_NORMALIZE_PATH],
+[case ":[$]$1:" in
+# change empty paths to '.'
+ ::) $1='.' ;;
+# strip trailing slashes
+ :*[[\\/]]:) $1=`echo "[$]$1" | sed 's,[[\\/]]*[$],,'` ;;
+ :*:) ;;
+esac
+# squeze repeated slashes
+case ifelse($2,,"[$]$1",$2) in
+# if the path contains any backslashes, turn slashes into backslashes
+
+# Bernhard Held 2003-04-06
+# This was the original line. It doesn't:
+# - convert the first slash
+# - replace a slash with a double-backslash
+# *\\*) $1=`echo "[$]$1" | sed 's,\(.\)[[\\/]][[\\/]]*,\1\\\\,g'` ;;
+ *\\*) $1=`echo "[$]$1" | sed 's,\(.\)[[\\/]][[\\/]]*,\1\\\\\\\\,g' | sed 's,^[[\\/]],\\\\\\\\,'` ;;
+
+# if the path contains slashes, also turn backslashes into slashes
+ *) $1=`echo "[$]$1" | sed 's,\(.\)[[\\/]][[\\/]]*,\1/,g'` ;;
+esac])
+
+
+# adl_COMPUTE_RELATIVE_PATH
+#
+# PATH_LIST is a space-separated list of colon-separated triplets of the form
+# 'FROM:TO:RESULT'. This function iterates over these triplets and set $RESULT
+# to the relative path from $FROM to $TO. Note that $FROM and $TO needs to be
+# absolute filenames for this macro to success.
+
+AC_DEFUN([adl_COMPUTE_RELATIVE_PATHS],
+[for _lcl_i in $1; do
+ _lcl_from=\[$]`echo "[$]_lcl_i" | sed 's,:.*$,,'`
+ _lcl_to=\[$]`echo "[$]_lcl_i" | sed 's,^[[^:]]*:,,' | sed 's,:[[^:]]*$,,'`
+ _lcl_result_var=`echo "[$]_lcl_i" | sed 's,^.*:,,'`
+ adl_RECURSIVE_EVAL([[$]_lcl_from], [_lcl_from])
+ adl_RECURSIVE_EVAL([[$]_lcl_to], [_lcl_to])
+ _lcl_notation="$_lcl_from$_lcl_to"
+ adl_NORMALIZE_PATH([_lcl_from],['/'])
+ adl_NORMALIZE_PATH([_lcl_to],['/'])
+ adl_COMPUTE_RELATIVE_PATH([_lcl_from], [_lcl_to], [_lcl_result_tmp])
+ adl_NORMALIZE_PATH([_lcl_result_tmp],["[$]_lcl_notation"])
+ eval $_lcl_result_var='[$]_lcl_result_tmp'
+done])
+
+## Note:
+## *****
+## The following helper macros are too fragile to be used out
+## of adl_COMPUTE_RELATIVE_PATHS (mainly because they assume that
+## paths are normalized), that's why I'm keeping them in the same file.
+## Still, some of them maybe worth to reuse.
+
+dnl adl_COMPUTE_RELATIVE_PATH(FROM, TO, RESULT)
+dnl ===========================================
+dnl Compute the relative path to go from $FROM to $TO and set the value
+dnl of $RESULT to that value. This function work on raw filenames
+dnl (for instead it will considerate /usr//local and /usr/local as
+dnl two distinct paths), you should really use adl_COMPUTE_REALTIVE_PATHS
+dnl instead to have the paths sanitized automatically.
+dnl
+dnl For instance:
+dnl first_dir=/somewhere/on/my/disk/bin
+dnl second_dir=/somewhere/on/another/disk/share
+dnl adl_COMPUTE_RELATIVE_PATH(first_dir, second_dir, first_to_second)
+dnl will set $first_to_second to '../../../another/disk/share'.
+AC_DEFUN([adl_COMPUTE_RELATIVE_PATH],
+[adl_COMPUTE_COMMON_PATH([$1], [$2], [_lcl_common_prefix])
+adl_COMPUTE_BACK_PATH([$1], [_lcl_common_prefix], [_lcl_first_rel])
+adl_COMPUTE_SUFFIX_PATH([$2], [_lcl_common_prefix], [_lcl_second_suffix])
+$3="[$]_lcl_first_rel[$]_lcl_second_suffix"])
+
+dnl adl_COMPUTE_COMMON_PATH(LEFT, RIGHT, RESULT)
+dnl ============================================
+dnl Compute the common path to $LEFT and $RIGHT and set the result to $RESULT.
+dnl
+dnl For instance:
+dnl first_path=/somewhere/on/my/disk/bin
+dnl second_path=/somewhere/on/another/disk/share
+dnl adl_COMPUTE_COMMON_PATH(first_path, second_path, common_path)
+dnl will set $common_path to '/somewhere/on'.
+AC_DEFUN([adl_COMPUTE_COMMON_PATH],
+[$3=''
+_lcl_second_prefix_match=''
+while test "[$]_lcl_second_prefix_match" != 0; do
+ _lcl_first_prefix=`expr "x[$]$1" : "x\([$]$3/*[[^/]]*\)"`
+ _lcl_second_prefix_match=`expr "x[$]$2" : "x[$]_lcl_first_prefix"`
+ if test "[$]_lcl_second_prefix_match" != 0; then
+ if test "[$]_lcl_first_prefix" != "[$]$3"; then
+ $3="[$]_lcl_first_prefix"
+ else
+ _lcl_second_prefix_match=0
+ fi
+ fi
+done])
+
+dnl adl_COMPUTE_SUFFIX_PATH(PATH, SUBPATH, RESULT)
+dnl ==============================================
+dnl Substrack $SUBPATH from $PATH, and set the resulting suffix
+dnl (or the empty string if $SUBPATH is not a subpath of $PATH)
+dnl to $RESULT.
+dnl
+dnl For instace:
+dnl first_path=/somewhere/on/my/disk/bin
+dnl second_path=/somewhere/on
+dnl adl_COMPUTE_SUFFIX_PATH(first_path, second_path, common_path)
+dnl will set $common_path to '/my/disk/bin'.
+AC_DEFUN([adl_COMPUTE_SUFFIX_PATH],
+[$3=`expr "x[$]$1" : "x[$]$2/*\(.*\)"`])
+
+dnl adl_COMPUTE_BACK_PATH(PATH, SUBPATH, RESULT)
+dnl ============================================
+dnl Compute the relative path to go from $PATH to $SUBPATH, knowing that
+dnl $SUBPATH is a subpath of $PATH (any other words, only repeated '../'
+dnl should be needed to move from $PATH to $SUBPATH) and set the value
+dnl of $RESULT to that value. If $SUBPATH is not a subpath of PATH,
+dnl set $RESULT to the empty string.
+dnl
+dnl For instance:
+dnl first_path=/somewhere/on/my/disk/bin
+dnl second_path=/somewhere/on
+dnl adl_COMPUTE_BACK_PATH(first_path, second_path, back_path)
+dnl will set $back_path to '../../../'.
+AC_DEFUN([adl_COMPUTE_BACK_PATH],
+[adl_COMPUTE_SUFFIX_PATH([$1], [$2], [_lcl_first_suffix])
+$3=''
+_lcl_tmp='xxx'
+while test "[$]_lcl_tmp" != ''; do
+ _lcl_tmp=`expr "x[$]_lcl_first_suffix" : "x[[^/]]*/*\(.*\)"`
+ if test "[$]_lcl_first_suffix" != ''; then
+ _lcl_first_suffix="[$]_lcl_tmp"
+ $3="../[$]$3"
+ fi
+done])
+
+
+dnl adl_RECURSIVE_EVAL(VALUE, RESULT)
+dnl =================================
+dnl Interpolate the VALUE in loop until it doesn't change,
+dnl and set the result to $RESULT.
+dnl WARNING: It's easy to get an infinite loop with some unsane input.
+AC_DEFUN([adl_RECURSIVE_EVAL],
+[_lcl_receval="$1"
+$2=`(test "x$prefix" = xNONE && prefix="$ac_default_prefix"
+ test "x$exec_prefix" = xNONE && exec_prefix="${prefix}"
+ _lcl_receval_old=''
+ while test "[$]_lcl_receval_old" != "[$]_lcl_receval"; do
+ _lcl_receval_old="[$]_lcl_receval"
+ eval _lcl_receval="\"[$]_lcl_receval\""
+ done
+ echo "[$]_lcl_receval")`])
+
+
+# AC_NORMALIZE_DEFINE_UNQUOTED(var, DEFINE, REFERENCE_STRING)
+
+AC_DEFUN([AC_NORMALIZE_DEFINE_UNQUOTED], [
+ ac_ndu=[$]$1
+ adl_NORMALIZE_PATH([ac_ndu], [$]$3)
+ AC_DEFINE_UNQUOTED($2, "${ac_ndu}")
+])
+