re PR target/54908 (misc regressions on emutls targets remain from dynamic initialization of non-function-local TLS variables)

	PR target/54908
c-family/
	* c.opt (-fextern-tls-init): New.
	* c-opts.c (c_common_post_options): Handle it.
cp/
	* decl2.c (get_local_tls_init_fn): New.
	(get_tls_init_fn): Handle flag_extern_tls_init.  Don't bother
	with aliases for internal variables.  Don't use weakrefs if
	the variable needs destruction.
	(generate_tls_wrapper): Mark the wrapper as const if no
	initialization is needed.
	(handle_tls_init): Don't require aliases.

From-SVN: r195310