hack based on Arjan van de Ven suggestion to reduce ELF footprint and

* elfgcchack.h doc/elfgcchack.xsl libxml.h: hack based on Arjan van de
  Ven suggestion to reduce ELF footprint and generated code. Based on
  aliasing of libraries function to generate direct call instead of
  indirect ones
* doc/libxml2-api.xml doc/Makefile.am doc/apibuild.py: added automatic
  generation of elfgcchack.h based on the API description, extended
  the API description to show the conditionals configuration flags
  required for symbols.
* nanohttp.c parser.c xmlsave.c include/libxml/*.h: lot of cleanup
* doc/*: regenerated the docs.
Daniel
diff --git a/xmlsave.c b/xmlsave.c
index 5b43c97..7698991 100644
--- a/xmlsave.c
+++ b/xmlsave.c
@@ -1357,7 +1357,6 @@
     return(ret);
 }
 
-#if 0
 /**
  * xmlSaveToBuffer:
  * @buffer:  a buffer
@@ -1368,14 +1367,13 @@
  * with the encoding and the options given
  *
  * Returns a new serialization context or NULL in case of error.
- */
 xmlSaveCtxtPtr
 xmlSaveToBuffer(xmlBufferPtr buffer, const char *encoding, int options)
 {
     TODO
     return(NULL);
 }
-#endif
+ */
 
 /**
  * xmlSaveToIO: