Re-examined the problems of configuring a "minimal" library.

Synchronized the header files with the library code in order
to assure that all the various conditionals (LIBXML_xxxx_ENABLED)
were the same in both.  Modified the API database content to more
accurately reflect the conditionals.  Enhanced the generation
of that database.  Although there was no substantial change to
any of the library code's logic, a large number of files were
modified to achieve the above, and the configuration script
was enhanced to do some automatic enabling of features (e.g.
--with-xinclude forces --with-xpath).  Additionally, all the format
errors discovered by apibuild.py were corrected.
* configure.in: enhanced cross-checking of options
* doc/apibuild.py, doc/elfgcchack.xsl, doc/libxml2-refs.xml,
  doc/libxml2-api.xml, gentest.py: changed the usage of the
  <cond> element in module descriptions
* elfgcchack.h, testapi.c: regenerated with proper conditionals
* HTMLparser.c, SAX.c, globals.c, tree.c, xmlschemas.c, xpath.c,
  testSAX.c: cleaned up conditionals
* include/libxml/[SAX.h, SAX2.h, debugXML.h, encoding.h, entities.h,
  hash.h, parser.h, parserInternals.h, schemasInternals.h, tree.h,
  valid.h, xlink.h, xmlIO.h, xmlautomata.h, xmlreader.h, xpath.h]:
  synchronized the conditionals with the corresponding module code
* doc/examples/tree2.c, doc/examples/xpath1.c, doc/examples/xpath2.c:
  added additional conditions required for compilation
* doc/*.html, doc/html/*.html: rebuilt the docs

include/libxml/valid.h

@@ -149,12 +149,6 @@ typedef xmlIDTable *xmlIDTablePtr;
 typedef struct _xmlHashTable xmlRefTable;
 typedef xmlRefTable *xmlRefTablePtr;
 
-/* Allocate/Release Validation Contexts */
-XMLPUBFUN xmlValidCtxtPtr XMLCALL	    
-		xmlNewValidCtxt(void);
-XMLPUBFUN void XMLCALL		    
-		xmlFreeValidCtxt(xmlValidCtxtPtr);
-
 /* Notation */
 XMLPUBFUN xmlNotationPtr XMLCALL	    
 		xmlAddNotationDecl	(xmlValidCtxtPtr ctxt,
@@ -162,8 +156,10 @@ XMLPUBFUN xmlNotationPtr XMLCALL
 					 const xmlChar *name,
 					 const xmlChar *PublicID,
 					 const xmlChar *SystemID);
+#ifdef LIBXML_TREE_ENABLED
 XMLPUBFUN xmlNotationTablePtr XMLCALL 
 		xmlCopyNotationTable	(xmlNotationTablePtr table);
+#endif /* LIBXML_TREE_ENABLED */
 XMLPUBFUN void XMLCALL		    
 		xmlFreeNotationTable	(xmlNotationTablePtr table);
 #ifdef LIBXML_OUTPUT_ENABLED
@@ -188,11 +184,13 @@ XMLPUBFUN void XMLCALL
 					 int size,
 	                                 xmlElementContentPtr content,
 					 int glob);
+#ifdef LIBXML_OUTPUT_ENABLED
 /* DEPRECATED */
 XMLPUBFUN void XMLCALL		     
 		xmlSprintfElementContent(char *buf,
 	                                 xmlElementContentPtr content,
 					 int glob);
+#endif /* LIBXML_OUTPUT_ENABLED */
 /* DEPRECATED */
 
 /* Element */
@@ -202,8 +200,10 @@ XMLPUBFUN xmlElementPtr XMLCALL
 					 const xmlChar *name,
 					 xmlElementTypeVal type,
 					 xmlElementContentPtr content);
+#ifdef LIBXML_TREE_ENABLED
 XMLPUBFUN xmlElementTablePtr XMLCALL 
 		xmlCopyElementTable	(xmlElementTablePtr table);
+#endif /* LIBXML_TREE_ENABLED */
 XMLPUBFUN void XMLCALL		   
 		xmlFreeElementTable	(xmlElementTablePtr table);
 #ifdef LIBXML_OUTPUT_ENABLED
@@ -220,8 +220,10 @@ XMLPUBFUN xmlEnumerationPtr XMLCALL
 		xmlCreateEnumeration	(const xmlChar *name);
 XMLPUBFUN void XMLCALL		   
 		xmlFreeEnumeration	(xmlEnumerationPtr cur);
+#ifdef LIBXML_TREE_ENABLED
 XMLPUBFUN xmlEnumerationPtr XMLCALL  
 		xmlCopyEnumeration	(xmlEnumerationPtr cur);
+#endif /* LIBXML_TREE_ENABLED */
 
 /* Attribute */
 XMLPUBFUN xmlAttributePtr XMLCALL	    
@@ -234,8 +236,10 @@ XMLPUBFUN xmlAttributePtr XMLCALL
 					 xmlAttributeDefault def,
 					 const xmlChar *defaultValue,
 					 xmlEnumerationPtr tree);
+#ifdef LIBXML_TREE_ENABLED
 XMLPUBFUN xmlAttributeTablePtr XMLCALL 
 		xmlCopyAttributeTable  (xmlAttributeTablePtr table);
+#endif /* LIBXML_TREE_ENABLED */
 XMLPUBFUN void XMLCALL		     
 		xmlFreeAttributeTable  (xmlAttributeTablePtr table);
 #ifdef LIBXML_OUTPUT_ENABLED
@@ -289,6 +293,12 @@ XMLPUBFUN xmlListPtr XMLCALL
  * The public function calls related to validity checking.
  */
 #ifdef LIBXML_VALID_ENABLED
+/* Allocate/Release Validation Contexts */
+XMLPUBFUN xmlValidCtxtPtr XMLCALL	    
+		xmlNewValidCtxt(void);
+XMLPUBFUN void XMLCALL		    
+		xmlFreeValidCtxt(xmlValidCtxtPtr);
+
 XMLPUBFUN int XMLCALL		
 		xmlValidateRoot		(xmlValidCtxtPtr ctxt,
 					 xmlDocPtr doc);
@@ -352,11 +362,14 @@ XMLPUBFUN int XMLCALL
 XMLPUBFUN int XMLCALL		
 		xmlValidateDocumentFinal(xmlValidCtxtPtr ctxt,
 					 xmlDocPtr doc);
+#endif /* LIBXML_VALID_ENABLED */
+
+#if defined(LIBXML_VALID_ENABLED) || defined(LIBXML_SCHEMAS_ENABLED)
 XMLPUBFUN int XMLCALL		
 		xmlValidateNotationUse	(xmlValidCtxtPtr ctxt,
 					 xmlDocPtr doc,
 					 const xmlChar *notationName);
-#endif /* LIBXML_VALID_ENABLED */
+#endif /* LIBXML_VALID_ENABLED or LIBXML_SCHEMAS_ENABLED */
 
 XMLPUBFUN int XMLCALL		
 		xmlIsMixedElement	(xmlDocPtr doc,
@@ -381,19 +394,19 @@ XMLPUBFUN xmlElementPtr XMLCALL
 		xmlGetDtdElementDesc	(xmlDtdPtr dtd,
 					 const xmlChar *name);
 
-XMLPUBFUN int XMLCALL		
-		xmlValidGetValidElements(xmlNode *prev,
-					 xmlNode *next,
-					 const xmlChar **names,
-					 int max);
+#ifdef LIBXML_VALID_ENABLED
+
 XMLPUBFUN int XMLCALL		
 		xmlValidGetPotentialChildren(xmlElementContent *ctree,
 					 const xmlChar **list,
 					 int *len,
 					 int max);
 
-#ifdef LIBXML_VALID_ENABLED
-
+XMLPUBFUN int XMLCALL		
+		xmlValidGetValidElements(xmlNode *prev,
+					 xmlNode *next,
+					 const xmlChar **names,
+					 int max);
 XMLPUBFUN int XMLCALL		
 		xmlValidateNameValue	(const xmlChar *value);
 XMLPUBFUN int XMLCALL		
@@ -403,7 +416,6 @@ XMLPUBFUN int XMLCALL
 XMLPUBFUN int XMLCALL		
 		xmlValidateNmtokensValue(const xmlChar *value);
 
-#endif /* LIBXML_VALID_ENABLED */
 #ifdef LIBXML_REGEXP_ENABLED
 /*
  * Validation based on the regexp support
@@ -427,6 +439,7 @@ XMLPUBFUN int XMLCALL
 					 xmlNodePtr elem,
 					 const xmlChar *qname);
 #endif /* LIBXML_REGEXP_ENABLED */
+#endif /* LIBXML_VALID_ENABLED */
 #ifdef __cplusplus
 }
 #endif