Dependency fix. We observed that doing any change to class THD in sql_class.h...

Dependency fix. We observed that doing any change to class THD in sql_class.h resulted in mysqld going crazy (parsing errors,
query cache errors in query_cache.test). This is because sql_yacc.cc depends on several .h files but those were not listed in
the dependencies of sql_yacc.o. The present patch does fix the issue; but my auto*-expert colleagues may have a better one.

sql/Makefile.am

@@ -108,7 +108,7 @@ gen_lex_hash.o:		gen_lex_hash.cc lex.h
 sql_yacc.cc:	sql_yacc.yy
 sql_yacc.h:	sql_yacc.yy
 
-sql_yacc.o:	sql_yacc.cc sql_yacc.h
+sql_yacc.o:	sql_yacc.cc sql_yacc.h $(noinst_HEADERS)
 		@echo "Note: The following compile may take a long time."
 		@echo "If it fails, re-run configure with --with-low-memory"
 		$(CXXCOMPILE) $(LM_CFLAGS) -c $<