Add compiler and linker hardening after the fact

[Jeffrey Walton]

Hi All,

I'm working on a system which includes binaries (not source code)
which do not utilize hardening techniques such as -z,relro -z,now,
-z,noexecstack, -znoexecheap, and -fPIE.

Does Binutils offer a tool to set the relevant bits (assuming the
binary is not signed nor integrity checked)? I'm not sure what needs
to be done for RELRO, NOW and PIE. I know -z,noexecstack, -znoexecheap
need new sections added for PT_GNU_STACK and PT_GNU_HEAP markings (and
no-exec heaps might not be available).

Jeff