The following parameters are now available:
* hardeningDisable
To disable specific hardening flags
* hardeningEnable
To enable specific hardening flags
Only the cc-wrapper supports this right now, but these may be reused by
other wrappers, builders or setup hooks.
cc-wrapper supports the following flags:
* fortify
* stackprotector
* pie (disabled by default)
* pic
* strictoverflow
* format
* relro
* bindnow
This removes the need for hacks like stdenv.regenerate. It also
ensures that overrideGCC is now stackable (so ‘stdenv = useGoldLinker
clangStdenv’ works).
