StarlingX/Security/Banned C Functions

Guidance
Prohibiting the use of banned functions is a good way to remove a significant number of potential code vulnerabilities from C and C++ code. This list is the compiled library of known bad functions that should be removed to reduce vulnerabilities. It is derived from experience with real-world security bugs and focuses primarily on functions that can lead to buffer overruns (reference: msdn).

Specifically, for Starling X, the main guidelines are that:
 * Only functions in the standard C runtime library—libc—are mandated
 * Unbounded functions are banned unless specifically noted
 * Stack allocation functions are banned unless specifically approved by the project core

There is no requirement to retrofit existing upstream code to meet these guidelines. A summary of the policy is provided below.

Color Coding