Make the package autoreconfigurable

Signed-off-by: Denis Bodor <lefinnois@lefinnois.net>

diff -ur libstrophe.orig/Makefile.am libstrophe/Makefile.am
--- libstrophe.orig/Makefile.am	2014-03-02 18:58:36.219753865 +0100
+++ libstrophe/Makefile.am	2014-03-02 18:58:02.739752477 +0100
@@ -1,4 +1,4 @@
-AUTOMAKE_OPTIONS = subdir-objects
+AUTOMAKE_OPTIONS = subdir-objects foreign
 
 CFLAGS = -g -Wall