[Ada] Declare time_t uniformly based on a system parameter

[Ada] Declare time_t uniformly based on a system parameter

gcc/ada/

	* Makefile.rtl: Add translations for s-parame__posix2008.ads
	* libgnarl/s-linux.ads: Import System.Parameters.
	(time_t): Declare using System.Parameters.time_t_bits.
	* libgnarl/s-linux__alpha.ads: Likewise.
	* libgnarl/s-linux__android.ads: Likewise.
	* libgnarl/s-linux__hppa.ads: Likewise.
	* libgnarl/s-linux__mips.ads: Likewise.
	* libgnarl/s-linux__riscv.ads: Likewise.
	* libgnarl/s-linux__sparc.ads: Likewise.
	* libgnarl/s-linux__x32.ads: Likewise.
	* libgnarl/s-qnx.ads: Likewise.
	* libgnarl/s-osinte__aix.ads: Likewise.
	* libgnarl/s-osinte__android.ads: Likewise.
	* libgnarl/s-osinte__darwin.ads: Likewise.
	* libgnarl/s-osinte__dragonfly.ads: Likewise.
	* libgnarl/s-osinte__freebsd.ads: Likewise.
	* libgnarl/s-osinte__gnu.ads: Likewise.
	* libgnarl/s-osinte__hpux-dce.ads: Likewise.
	* libgnarl/s-osinte__hpux.ads: Likewise.
	* libgnarl/s-osinte__kfreebsd-gnu.ads: Likewise.
	* libgnarl/s-osinte__lynxos178e.ads: Likewise.
	* libgnarl/s-osinte__qnx.ads: Likewise.
	* libgnarl/s-osinte__rtems.ads: Likewise.
	* libgnarl/s-osinte__solaris.ads: Likewise.
	* libgnarl/s-osinte__vxworks.ads: Likewise.
	* libgnat/g-sothco.ads: Likewise.
	* libgnat/s-osprim__darwin.adb: Likewise.
	* libgnat/s-osprim__posix.adb: Likewise.
	* libgnat/s-osprim__posix2008.adb: Likewise.
	* libgnat/s-osprim__rtems.adb: Likewise.
	* libgnat/s-osprim__x32.adb: Likewise.
	* libgnarl/s-osinte__linux.ads: use type System.Linux.time_t.
	* libgnat/s-os_lib.ads (time_t): Declare as subtype of
	Long_Long_Integer.
	* libgnat/s-parame.ads (time_t_bits): New constant.
	* libgnat/s-parame__ae653.ads (time_t_bits): Likewise.
	* libgnat/s-parame__hpux.ads (time_t_bits): Likewise.
	* libgnat/s-parame__vxworks.ads (time_t_bits): Likewise.
	* libgnat/s-parame__posix2008.ads: New file for 64 bit time_t.