* i386.cc (Target_i386::Relocate::relocate_tls): Set dynamic type

	* i386.cc (Target_i386::Relocate::relocate_tls): Set dynamic type
	for TLS_GOTDESC and TLS_DESC_CALL.  Only optimize TLS_LDO_32 if we
	know the dynamic type.
	* x86_64.cc (Target_x86_64::Relocate): Add saw_tls_block_reloc_
	field.  Initialize it in constructor.
	(Target_x86_64::Relocate::relocate_tls): Record that we saw a TLS
	block reloc for TLSGD, GOTPC32_TLSDESC, TLSDESC_CALL, and TLSLD.
	Only optimize DTPOFF32 and DTPOFF64 if we have seen a TLS block
	reloc.