Adds dynamic stack cookies in the form of copies of the entry
point libraries that use shared logic to update stack cookies
at runtime.
This relies on RDRAND on IA32/X64 and RNDR on AARCH64 to get a
random number to apply to the stack cookie on module entry point.
This simplifies the logic a platform must do to include stack
check functionality.
Signed-off-by: Oliver Smith-Denny <osde@microsoft.com>