libev: fixed to run autoreconf because we patch configure.ac

develop/libev/libev.conf

@@ -2,7 +2,7 @@
 # This copyright note is auto-generated by ./scripts/Create-CopyPatch.
 #
 # Filename: package/.../libev/libev.conf
-# Copyright (C) 2008 The OpenSDE Project
+# Copyright (C) 2008 - 2011 The OpenSDE Project
 #
 # More information can be found in the files COPYING and README.
 #
@@ -17,3 +17,6 @@ if pkginstalled libevent; then
 
 	var_append patchfiles ' ' "$confdir/no_compat.diff"
 fi
+
+# we patch configure.ac
+hook_add preconf 9 'autoreconf -vfi'