This version of the MAC address parser allows number of different
string formats for the address (e.g., 00:11:22:33:44:55, 0011.2233.4455,
001122334455, 00-11-22-33-44-55). It returns the number of characters
used from the input string in case of success.
gcc 4.4 ends up generating strict-aliasing warnings about some very common
networking socket uses that do not really result in a real problem and
cannot be easily avoided with union-based type-punning due to struct
definitions including another struct in system header files. To avoid having
to fully disable strict-aliasing warnings, provide a mechanism to hide the
typecast from aliasing for now. A cleaner solution will hopefully be found
in the future to handle these cases.
