#8 Add section on the misuse of macros.
Merged by huzaifas. Opened by wmealing.
wmealing/defensive-coding-guide macros-misuse  into  master

First pull ive done for this project, let me know if it should be in another location. This outlines the possible misuse of macros and the automated expansion by the c pre-processor.

Metadata Update from @huzaifas:
- Request assigned

Thanks for your PR, does any one want to review this one?

Pull-Request has been merged by huzaifas