Functions for embedders to override

Since we're running into Ponie issues with this, which means we'll 
run into Apache issues as well as any number of other systems....

When Parrot's being embedded I can see the following functions 
needing overriding by the embedder:

*) Memory: malloc, realloc, calloc, free
*) Signals: handler register, Handler un-register, signal raise, alarm set
*) Files: Open, close, seek, tell, read, write. (Possibly asynchronously)

I want to get these defined and a system in place to allow overriding 
functions to be registered to give embedders control over parrot's 
interface to the 'real world', and so we can get the source fixed up 
now, rather than put it off even more.
-- 
				Dan

--------------------------------------it's like this-------------------
Dan Sugalski                          even samurai
[email protected]                         have teddy bears and even
                                       teddy bears get drunk