[PATCH] elf: Make non-executable stack disable by default

[Florian Weimer]

* Adhemerval Zanella:

> +* A new tunable, glibc.rtld.noexecstack, can be used to enable executable
> +  stacks from either main program, dependencies, or dynamically loadeed
> +  libraries.  The default is to disable executable stacks.

Typo: “load[e]d”

Should we refuse to enable executable stack on dlopen by default?  And
only enable it if the initial set of objects request executable stack?

Thanks,
Florian