elf: Move LAV_CURRENT to link_lavcurrent.h

No functional change.

bits/link_lavcurrent.h

@@ -0,0 +1,25 @@
+/* Data structure for communication from the run-time dynamic linker for
+   loaded ELF shared objects.  LAV_CURRENT definition.
+   Copyright (C) 2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _LINK_H
+# error "Never include <bits/link_lavcurrent.h> directly; use <link.h> instead."
+#endif
+
+/* Version numbers for la_version handshake interface.  */
+#define LAV_CURRENT	1

elf/Makefile

@@ -21,7 +21,7 @@ subdir		:= elf
 
 include ../Makeconfig
 
-headers		= elf.h bits/elfclass.h link.h bits/link.h
+headers		= elf.h bits/elfclass.h link.h bits/link.h bits/link_lavcurrent.h
 routines	= $(all-dl-routines) dl-support dl-iteratephdr \
 		  dl-addr dl-addr-obj enbl-secure dl-profstub \
 		  dl-origin dl-libc dl-sym dl-sysdep dl-error \

elf/link.h

@@ -113,7 +113,7 @@ struct link_map
 #ifdef __USE_GNU
 
 /* Version numbers for la_version handshake interface.  */
-#define LAV_CURRENT	1
+#include <bits/link_lavcurrent.h>
 
 /* Activity types signaled through la_activity.  */
 enum