Y2038: provide size of default time_t for target architecture

Y2038: provide size of default time_t for target architecture

    To determine whether the default time_t interfaces are 32-bit
    and so need conversions, or are 64-bit and so are compatible
    with the internal 64-bit type without conversions, a macro
    giving the size of the  default time_t is also required.
    This macro is called __TIMESIZE.

    This macro can then be used instead of __WORDSIZE in msq-pad.h
    and shm-pad.h files, which in turn allows removing their x86
    variants, and in sem-pad.h files but keeping the x86 variant.

    This patch was tested by running 'make check' on branch master
    then applying this patch and running 'make check' again, and
    checking that both 'make check' yield identical results.
    This was done on x86_64-linux-gnu and i686-linux-gnu.

	* bits/timesize.h: New file.
	* stdlib/Makefile (headers): Add bits/timesize.h.
	* sysdeps/unix/sysv/linux/bits/msq-pad.h
	(__MSQ_PAD_AFTER_TIME): Use __TIMESIZE instead of __WORDSIZE.
	* sysdeps/unix/sysv/linux/bits/sem-pad.h
	(__SEM_PAD_AFTER_TIME): Likewise.
	* sysdeps/unix/sysv/linux/bits/shm-pad.h
	(__SHM_PAD_AFTER_TIME): Likewise.
	* sysdeps/unix/sysv/linux/hppa/bits/msq-pad.h
	(__MSQ_PAD_BEFORE_TIME): Likewise.
	* sysdeps/unix/sysv/linux/hppa/bits/sem-pad.h
	(__SEM_PAD_BEFORE_TIME): Likewise.
	* sysdeps/unix/sysv/linux/hppa/bits/shm-pad.h
	(__SHM_PAD_BEFORE_TIME, __SHM_PAD_BETWEEN_TIME_AND_SEGSZ): Likewise.
	* sysdeps/unix/sysv/linux/mips/bits/msq-pad.h
        (__MSQ_PAD_AFTER_TIME, __MSQ_PAD_BEFORE_TIME): Likewise.
        * sysdeps/unix/sysv/linux/powerpc/bits/msq-pad.h
        (__MSQ_PAD_BEFORE_TIME): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/bits/sem-pad.h
	(__SEM_PAD_BEFORE_TIME): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/bits/shm-pad.h
	(__SHM_PAD_BEFORE_TIME, __SHM_PAD_BETWEEN_TIME_AND_SEGSZ): Likewise.
	* sysdeps/unix/sysv/linux/sparc/bits/msq-pad.h
	(__MSQ_PAD_BEFORE_TIME): Likewise.
	* sysdeps/unix/sysv/linux/sparc/bits/sem-pad.h
	(__SEM_PAD_BEFORE_TIME): Likewise.
	* sysdeps/unix/sysv/linux/sparc/bits/shm-pad.h
	(__SHM_PAD_BEFORE_TIME): Likewise.
	* sysdeps/unix/sysv/linux/x86/bits/msq-pad.h: Delete file.
	* sysdeps/unix/sysv/linux/x86/bits/shm-pad.h: Likewise.
	* sysdeps/unix/sysv/linux/x86/bits/timesize.h: New file.