[hurd,commited]: Fix static initialization with -fstack-protector-strong

[Nick Alcock]

On 27 Aug 2017, Samuel Thibault outgrape:

>     When linked statically, TLS initialization is not achieved before
>     mach_init and alike, so ssp accesses to tcbhead's stack_guard would
>     crash.  We can just avoid using ssp in the few functions needed before
>     TLS is set up.

Oh blast I forgot all about Hurd didn't I.

Sorry.

> diff --git a/hurd/Makefile b/hurd/Makefile
> index 9205822b24..b44b9b80c6 100644
> --- a/hurd/Makefile
> +++ b/hurd/Makefile
> @@ -81,6 +81,10 @@ $(inlines:%=$(objpfx)%.c): $(objpfx)%-inlines.c: %.h
>  	 echo '#include "$<"') > $@-new
>  	mv -f $@-new $@
>  generated += $(inlines:=.c)
> +
> +# Avoid ssp before TLS is initialized.
> +CFLAGS-hurdstartup.o = $(no-stack-protector)
> +CFLAGS-RPC_exec_startup_get_info.o = $(no-stack-protector)

This certainly looks like the right sort of thing to be doing, though I
don't have anything I can test it on right now.

-fstack-protector-all might well comb out some more cases.

-- 
NULL && (void)