Add more system_* checks

[GoogleCodeExporter]

Add more system_* checks:
* GrSecurity
* Heap hardening
* GCC stack protector
* Strict user copy checks
* Read-only kernel data
* Restricted /dev/mem
* Restricted /dev/kmem

Original issue reported on code.google.com by bernardo.damele on 1 Nov 2012 at 1:09