patch Charles Bozeman for validation of all the date, time, and duration

* xmlschemastypes.c: patch Charles Bozeman for validation of
  all the date, time, and duration types
* test/schemas/dur_0* result/schemas/dur_0*: associated tests
* configure.in: fixed an error pointed by an user
* xml2-config.in: fixed an error pointed by an user
Daniel
diff --git a/result/schemas/dur_0_0 b/result/schemas/dur_0_0
new file mode 100644
index 0000000..5b3a2c9
--- /dev/null
+++ b/result/schemas/dur_0_0
@@ -0,0 +1 @@
+./test/schemas/dur_0.xml validates