Remove INTDEF / INTUSE / INTVARDEF (bug 14132).

Remove INTDEF / INTUSE / INTVARDEF (bug 14132).

Completing the removal of the obsolete INTDEF / INTUSE mechanism, this
patch removes the final use - that for _dl_starting_up - replacing it
by rtld_hidden_def / rtld_hidden_proto.  Having removed the last use,
the mechanism itself is also removed.

Tested for x86_64 that installed stripped shared libraries are
unchanged by the patch.  (This is not much of a test since this
variable is only defined and used in the !HAVE_INLINED_SYSCALLS case.)

	[BZ #14132]
	* include/libc-symbols.h (INTUSE): Remove macro.
	(INTDEF): Likewise.
	(INTVARDEF): Likewise.
	(_INTVARDEF): Likewise.
	(INTDEF2): Likewise.
	(INTVARDEF2): Likewise.
	* elf/rtld.c [!HAVE_INLINED_SYSCALLS] (_dl_starting_up): Use
	rtld_hidden_def instead of INTVARDEF.
	* sysdeps/generic/ldsodefs.h [IS_IN_rtld]
	(_dl_starting_up_internal): Remove declaration.
	(_dl_starting_up): Use rtld_hidden_proto.
	* elf/dl-init.c [!HAVE_INLINED_SYSCALLS] (_dl_starting_up): Remove
	declaration.
	[!HAVE_INLINED_SYSCALLS] (_dl_starting_up_internal): Likewise.
	(_dl_init) [!HAVE_INLINED_SYSCALLS]: Don't use INTUSE with
	_dl_starting_up.
	* elf/dl-writev.h (_dl_writev): Likewise.
	* sysdeps/powerpc/powerpc64/dl-machine.h [!HAVE_INLINED_SYSCALLS]
	(DL_STARTING_UP_DEF): Use __GI__dl_starting_up instead of
	_dl_starting_up_internal.