Need to sync GC objects to stack only during atomic GC phase.
Need to setup a proper frame structure only for calling finalizers.
Force an exit to the interpreter and let it handle the uncommon cases.
Finally solves the "NYI: gcstep sync with frames" issue.
Drop call gates. Use function headers, dispatched like bytecodes.
Emit BC_FUNCF/BC_FUNCV bytecode at PC 0 for all Lua functions.
C functions and ASM fast functions get extra bytecodes.
Modify internal calling convention: new base in BASE (formerly in RA).
Can now use better C function wrapper semantics (dynamic on/off).
Prerequisite for call hooks with zero-overhead if disabled.
Prerequisite for compiling recursive calls.
Prerequisite for efficient 32/64 bit prototype guards.
Only works with DWARF2-enabled GCC 4.x (not the default MinGW GCC).
Fix fastcall symbol names for COFF assembler output.
Add DWARF2 unwind info to COFF assembler output.
Use COFF assembler mode for MinGW builds.
Always enable the DWARF2 handler if compiled with GCC.
