core: Convert internal macros to static inline functions

core: Convert internal macros to static inline functions

Older versions of the Visual Studio compiler are picky about macros
constructed with the 'do { ... } while (0)' construct. Convert these
internal ones to static inline functions. The result is functionally
equivalent but gets us type checking and a bit more readability.

Also address some compiler warnings due to some header files that are
being included in a different order than before.

Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>