Regenerated API and symbols

* doc/Makefile.am: make the check for symbols pbm a make api failure
* doc/symbols.xml: added xmlXIncludeProcessTreeFlagsData
* doc//* elfgcchack.h libxml2.syms testapi.c: regenerated
diff --git a/doc/symbols.xml b/doc/symbols.xml
index be22117..b4d9082 100644
--- a/doc/symbols.xml
+++ b/doc/symbols.xml
@@ -1739,5 +1739,6 @@
   </release>
   <release version="2.7.4">
     <symbol file="globals">xmlStructuredErrorContext</symbol>
+    <symbol file="xinclude">xmlXIncludeProcessTreeFlagsData</symbol>
   </release>
 </symbols>