Make newline in RHS of lib/configure sed substition more portable

Commit 1b78e85 introduces a non-portable escaped newline
character in the substitution string. It does not work as
expected.

On a Linux machine it inserts an additional blank line
and on OSX it only inserts a leading 'n' which gives you
a broken lib/configure script.

Signed-off-by: Tuncer Ayaz <tuncer.ayaz@gmail.com>

otp_build

@@ -1,20 +1,20 @@
 #! /bin/sh
 #
 # %CopyrightBegin%
-# 
+#
 # Copyright Ericsson AB 2002-2010. All Rights Reserved.
-# 
+#
 # The contents of this file are subject to the Erlang Public License,
 # Version 1.1, (the "License"); you may not use this file except in
 # compliance with the License. You should have received a copy of the
 # Erlang Public License along with this software. If not, it can be
 # retrieved online at http://www.erlang.org/.
-# 
+#
 # Software distributed under the License is distributed on an "AS IS"
 # basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 # the License for the specific language governing rights and limitations
 # under the License.
-# 
+#
 # %CopyrightEnd%
 #
 
@@ -225,6 +225,8 @@ set_config_flags ()
 	export CONFIG_FLAGS;
 }
 
+NL="\
+"
 create_lib_configure_in()
 {
     cd $ERL_TOP
@@ -241,7 +243,7 @@ create_lib_configure_in()
 	    lib/*)
 		if [ -f "$lib_app/configure.in" ]; then
 		    app=`echo "$lib_app" | sed "s|lib/\(.*\)|\1|"`
-		    sdirs="${sdirs}test ! -f $app/configure || AC_CONFIG_SUBDIRS($app/.)\n"
+		    sdirs="${sdirs}test ! -f $app/configure || AC_CONFIG_SUBDIRS($app/.)${NL}"
 		fi;;
 	    *)
 		;;
@@ -258,7 +260,7 @@ create_lib_configure_in()
 	done
 	if [ $is_bapp = false ] && [ -f "$lib_app/configure.in" ]; then
 	    app=`echo "$lib_app" | sed "s|lib/\(.*\)|\1|"`
-	    sdirs="${sdirs}    test ! -f $app/configure || AC_CONFIG_SUBDIRS($app/.)\n"
+	    sdirs="${sdirs}    test ! -f $app/configure || AC_CONFIG_SUBDIRS($app/.)${NL}"
 	fi
     done