making DSO support an option code and documentation cleanups regenerated

* configure.in: making DSO support an option
* xmlmodule.c xmlreader.c include/libxml/xmlmodule.h: code
  and documentation cleanups
* elfgcchack.h testapi.c doc/*: regenerated the docs and
  checks for new module
* test/valid/REC-xml-19980210.xml: fix a small change introduced
  previously
Daniel
diff --git a/doc/apibuild.py b/doc/apibuild.py
index bcc1463..bd88a18 100755
--- a/doc/apibuild.py
+++ b/doc/apibuild.py
@@ -33,6 +33,7 @@
   "rngparser.h": "not yet integrated",
   "elfgcchack.h": "not a normal header",
   "testapi.c": "generated regression tests",
+  "testdso.c": "test for dynamid shared libraries",
 }
 
 ignored_words = {