Because of gcc -Wmissing-prototypes, all functions in dynamically
loadable modules must have a separate prototype declaration. This is
meant to detect global functions that are not declared in header files,
but in cases where the function is called via dfmgr, this is redundant.
Besides filling up space with boilerplate, this is a frequent source of
compiler warnings in extension modules.
We can fix that by creating the function prototype as part of the
PG_FUNCTION_INFO_V1 macro, which such modules have to use anyway. That
makes the code of modules cleaner, because there is one less place where
the entry points have to be listed, and creates an additional check that
functions have the right prototype.
Remove now redundant prototypes from contrib and other modules.
Both dict_int and dict_xsyn were blithely assuming that whatever memory
palloc gives back will be pre-zeroed. This would typically work for
just about long enough to run their regression tests, and no longer :-(.
The pre-9.0 code in dict_xsyn was even lamer than that, as it would
happily give back a pointer to the result of palloc(0), encouraging
its caller to access off the end of memory. Again, this would just
barely fail to fail as long as memory contained nothing but zeroes.
Per a report from Rodrigo Hjort that code based on these examples
didn't work reliably.
