nitg/ffi: mark as private methods internal to compiler_ffi

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
ffi/java: callbacks are relative to mainmodule

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
ffi/java: use C callbacks instead of going straight to nitni (for global)

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
ffi: minor clean up

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
android: support use of -m

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>