[PATCH] debian: enable build hardening features

[David Bremner]

Daniel Kahn Gillmor <dkg at fifthhorseman.net> writes:

> Debian's build hardening toolchain options produce binary artifacts
> that are more resistant to compromise.  The most visible change for
> notmuch today is likely to be the addition of the "bindnow" linker
> flag, which contributes to making the "Global Offset Table" fully
> read-only.
>

pushed to master.

d