Use static and __{BEGIN,ENV}_HIDDEN_DECLS to hide a bunch of internal

symbols that are not longer exported.  (This improves the generated code.)
ok deraadt@

src/include/db.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: db.h,v 1.9 2012/12/05 23:19:57 deraadt Exp $	*/
+/*	$OpenBSD: db.h,v 1.10 2015/08/27 04:37:09 guenther Exp $	*/
 /*	$NetBSD: db.h,v 1.13 1994/10/26 00:55:48 cgd Exp $	*/
 
 /*-
@@ -207,12 +207,14 @@ typedef struct {
 
 __BEGIN_DECLS
 DB *dbopen(const char *, int, int, DBTYPE, const void *);
+__END_DECLS
 
 #ifdef __DBINTERFACE_PRIVATE
+__BEGIN_HIDDEN_DECLS
 DB	*__bt_open(const char *, int, int, const BTREEINFO *, int);
 DB	*__hash_open(const char *, int, int, const HASHINFO *, int);
 DB	*__rec_open(const char *, int, int, const RECNOINFO *, int);
 void	 __dbpanic(DB *dbp);
+__END_HIDDEN_DECLS
 #endif
-__END_DECLS
 #endif /* !_DB_H_ */