[PMC] cannot share functions between PMC

[fperrad]

Since r38536 (tt631_part2 merge), we cannot share functions (VTABLE & MULTI) between PMC in the same group.

For example, LuaString PMC calls code from LuaNumber PMC (VTABLE & MULTI).

The linking is broken, because all functions are now 'static'.

[bacek]

Replying to fperrad:

Since r38536 (tt631_part2 merge), we cannot share functions (VTABLE & MULTI) between PMC in the same group.

There is two sides of this problem:

1. No one should call vtable function directly. Described in #528 and #631. Unfortunately Pmc2c/MethodEmitter.pm still emits direct calls sometimes. E.g. for OtherClass.pmc.method. My personal option - remove handling of this mapping at all. But for now I'll try to fix generated code.

2. Second realted problem - lua uses direct calls to MULTI functions. I can help with replacing such calls with "Parrot_mmd_multi_dispatch".

-- Bacek

[fperrad]

successful refactor of Lua PMC with these new constraints.