From 211e79cccffa9a4609b1dbaca0cf4d7a1969fc59 Mon Sep 17 00:00:00 2001
From: Stefan Seyfried <seife@tuxbox-git.slipkontur.de>
Date: Fri, 10 May 2013 13:22:27 +0200
Subject: [PATCH] acinclude: fix variable expansion issues

Origin commit data
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Branch: master
Commit: https://github.com/neutrino-images/ni-libstb-hal/commit/2b23273b0e0b594d5f31e2a8cc470e8ad8fe341d
Author: Stefan Seyfried <seife@tuxbox-git.slipkontur.de>
Date: 2013-05-10 (Fri, 10 May 2013)


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No further description and justification available within origin commit message!

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This commit was generated by Migit
---
 acinclude.m4 | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/acinclude.m4 b/acinclude.m4
index da7449e..5662e5a 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -57,21 +57,33 @@ check_path () {
 
 ])
 
+dnl expand nested ${foo}/bar
+AC_DEFUN([TUXBOX_EXPAND_VARIABLE],[__$1="$2"
+	for __CNT in false false false false true; do dnl max 5 levels of indirection
+
+		$1=`eval echo "$__$1"`
+		echo ${$1} | grep -q '\$' || break # 'grep -q' is POSIX, exit if no $ in variable
+		__$1="${$1}"
+	done
+	$__CNT && AC_MSG_ERROR([can't expand variable $1=$2]) dnl bail out if we did not expand
+])
+
 AC_DEFUN([TUXBOX_APPS_DIRECTORY_ONE],[
 AC_ARG_WITH($1,[  $6$7 [[PREFIX$4$5]]],[
 	_$2=$withval
 	if test "$TARGET" = "cdk"; then
-		$2=`eval echo "${targetprefix}$withval"`
+		$2=`eval echo "${targetprefix}$withval"` # no indirection possible IMNSHO
 	else
 		$2=$withval
 	fi
 	TARGET_$2=${$2}
 ],[
-	$2="\${$3}$5"
+	# RFC 1925: "you can always add another level of indirection..."
+	TUXBOX_EXPAND_VARIABLE($2,"${$3}$5")
 	if test "$TARGET" = "cdk"; then
-		_$2=`eval echo "${target$3}$5"`
+		TUXBOX_EXPAND_VARIABLE(_$2,"${target$3}$5")
 	else
-		_$2=`eval echo "${$3}$5"`
+		_$2=${$2}
 	fi
 	TARGET_$2=$_$2
 ])