Made spec file autogenerate, tweaked it also

Dr Mike <drmike@redhat.com>
diff --git a/configure.in b/configure.in
index fb6b513..30a7d8e 100644
--- a/configure.in
+++ b/configure.in
@@ -62,5 +62,5 @@
 AC_FUNC_STRFTIME
 AC_CHECK_FUNCS(strdup strndup strerror snprintf )
 AC_SUBST(Z_LIBS)
-AC_OUTPUT(Makefile doc/Makefile xml-config)
+AC_OUTPUT(libxml.spec Makefile doc/Makefile xml-config)