Don't use INTVARDEF/INTUSE with __libc_enable_secure (bug 14132).

Continuing the removal of the obsolete INTDEF / INTVARDEF / INTUSE
mechanism, this patch replaces its use for __libc_enable_secure with
the use of rtld_hidden_data_def and rtld_hidden_proto.

Tested for x86_64 that installed stripped shared libraries are
unchanged by the patch.

	[BZ #14132]
	* elf/dl-sysdep.c (__libc_enable_secure): Use rtld_hidden_data_def
	instead of INTVARDEF.
	(_dl_sysdep_start): Do not use INTUSE with __libc_enable_secure.
	* sysdeps/mach/hurd/dl-sysdep.c (__libc_enable_secure): Use
	rtld_hidden_data_def instead of INTVARDEF.
	(_dl_sysdep_start): Do not use INTUSE with __libc_enable_secure.
	* elf/dl-deps.c (expand_dst): Likewise.
	* elf/dl-load.c (_dl_dst_count): Likewise.
	(_dl_dst_substitute): Likewise.
	(decompose_rpath): Likewise.
	(_dl_init_paths): Likewise.
	(open_path): Likewise.
	(_dl_map_object): Likewise.
	* elf/rtld.c (dl_main): Likewise.
	(process_dl_audit): Likewise.
	(process_envvars): Likewise.
	* include/unistd.h [IS_IN_rtld] (__libc_enable_secure_internal):
	Remove declaration.
	(__libc_enable_secure): Use rtld_hidden_proto.
Remove CANCEL-FCT-WAIVE and CANCEL-FILE-WAIVE.

As far as I can tell, CANCEL-FCT-WAIVE and CANCEL-FILE-WAIVE are old
notes from the addition of cancellation support to glibc and are not
currently used by any glibc testcases or otherwise in the build
process, and it does not seem useful to me to keep them around.  This
patch removes them.

Tested for x86_64.

	* CANCEL-FCT-WAIVE: Remove file.
	* CANCEL-FILE-WAIVE: Likewise.