--- ./configure.orig	2010-04-04 11:02:40.000000000 +0200
+++ ./configure	2010-11-22 19:41:52.000000000 +0100
@@ -92,7 +92,7 @@
 {
     local var val A
 
-    [ "$(sed -e 's/--[^=]\+=[^=]*/AA/' <<< $1)" != AA ] && return 1
+    [ "$(sed -E -e 's/--[^=]+=[^=]*/AA/' <<< $1)" != AA ] && return 1
 
     A=${1:2}
     var=${A%%=*}
@@ -167,7 +167,7 @@
 
 function check_feature ()
 {
-    [ "$(sed  -e 's/--\(enable\|disable\)-.\+/AA/' <<< $1)" != AA ] && return 1
+    [ "$(sed -E -e 's/--(enable|disable)-.+/AA/' <<< $1)" != AA ] && return 1
     A=${1:2}
     var=${A#*-}
     val=${A%%-*}