* i386.cc (class Target_i386): Add got_tlsdesc_ field.

	* i386.cc (class Target_i386): Add got_tlsdesc_ field.
	(Target_i386::Target_i386):: Initialize got_tlsdesc_.
	(Target_i386::got_tlsdesc_section): New function.
	(Target_i386::got_section): Create space for GOT entries for
	TLSDESC relocations.
	(Target_i386::Scan::local): Use TLSDESC GOT for unoptimized
	R_386_TLS_GOTDESC.
	(Target_i386::Scan::global): Likewise.
	(Target_i386::Relocate::relocate_tls): Adjust GOT offset when
	using TLSDESC GOT.
	* x86_64.cc (class Target_x86_64): Add got_tlsdesc_ field.
	(Target_x86_64::Target_x86_64):: Initialize got_tlsdesc_.
	(Target_x86_64::got_tlsdesc_section): New function.
	(Target_x86_64::got_section): Create space for GOT entries for
	TLSDESC relocations.
	(Target_x86_64::Scan::local): Use TLSDESC GOT for unoptimized
	R_386_TLS_GOTDESC.
	(Target_x86_64::Scan::global): Likewise.
	(Target_x86_64::Relocate::relocate_tls): Adjust GOT offset when
	using TLSDESC GOT.