Update.

Update.

	* sysdeps/generic/enbl-secure.c (__libc_enable_secure_decided): New
	variable.
	(__libc_init_secure): Don't do anything if __libc_enable_secure_decided
	is nonzero.
	* include/unistd.h: Declare __libc_enable_secure_decided.
	* elf/dl-support.c (_dl_aux_init): Recognize AT_UID, AT_EUID, AT_GID,
	and AT_EGID.  If all found, set __libc_enable_secure and
	__libc_enable_secure_decided.