[libxml2] Fix compilation with --with-minimum

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 0f518611542115e0322acb60868750697ca03aab
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Mon Apr 8 14:02:11 2019 +0200

    Fix compilation with --with-minimum
    
    Presence of xmlEncodeAttributeEntities doesn't depend on output module.
    
    Fixes #52.

 save.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/save.h b/save.h
index 2c32a103..753aaef5 100644
--- a/save.h
+++ b/save.h
@@ -25,9 +25,10 @@ void xmlBufDumpNotationTable(xmlBufPtr buf, xmlNotationTablePtr table);
 void xmlBufDumpElementDecl(xmlBufPtr buf, xmlElementPtr elem);
 void xmlBufDumpAttributeDecl(xmlBufPtr buf, xmlAttributePtr attr);
 void xmlBufDumpEntityDecl(xmlBufPtr buf, xmlEntityPtr ent);
-xmlChar *xmlEncodeAttributeEntities(xmlDocPtr doc, const xmlChar *input);
 #endif
 
+xmlChar *xmlEncodeAttributeEntities(xmlDocPtr doc, const xmlChar *input);
+
 #ifdef __cplusplus
 }
 #endif