MFC 4cd1807c7d2a67b633dd0c0bfde15091543a2514:
Retire the K&R/STD C __P prototype declarations.
In the old days when K&R C and STD C were each in use a workaround
(read hack) was required to allow the same code to work on each
without modification. All C compilers support STD C. We can finally
put the __P prototype to rest.
(cherry picked from commit 4cd1807c7d2a67b633dd0c0bfde15091543a2514)