gnumach code cleanup

[Marin Ramesa]

I've broken up my previous patch into seperate git commits and
added the removal of forward declarations. The result is a series
of 68 patches. I am sorry of the length of the series causes any
trouble. Large number of forward declarations have been turned into
prototypes in header files and all K&R style function definitions
have been turned into ANSI style function definitions along with 
other small changes. This patch series produces new warnings from
GCC.