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
