[jx8-ios] Extending jxcore with internal module for s8

Adding module files to project

1. New folder for source files at src/s8
2. Add two files (s8_ffi.h and s8_ffi.cc) for sources of s8-ffi module at src/s8
3. Add a new line to file node_extensions.h to register node_s8_ffi module in (internal) node extensions list
4. Add 'src/s8/s8_ffi.cc' to jx.gpy after line 'src/wrappers/node_zlib.cc'; to ensure our module will be included in build

Building the jxcore

1. Open terminal window and cd to root of jxcore project folder
2. execute build script
   ./build_scripts/ios_compile.sh
3. it is not smalltalk, so relax and wait the build to finish

Installing the new jxcore engine

1. copy the folders (bin and include) under out_ios/ios to jx8-ios project under jx8-ios/jxcore

Running jx8-ios and accessing our new s8 binding

1. Run jx8-ios in the device with xcode debug
2. Connect a workspace from desktop U8 contribution
3. To access the s8 library evaluate with showIt
   • NodeJS process handle #binding: #s8_ffi
   • Note: it will trigger an error if the binding is not installed
4. To see the methods published by the library evaluate with showIt
   • JS@>(NodeJS process handle #binding: #s8_ffi)

Initializing the bindings

| obj cif nargs rtype atypes abi |
obj := Object new json.
(NodeJS process handle #binding: #s8_ffi)
	#initializeBindings: obj.
JS@>obj['FFI_TYPES'].
JS@>obj['StaticFunctions'][#dlopen].
{'cif = new Buffer("hello");'}.
nargs := 0.
rtype := #void.
atypes := #aTypes.
abi := 1.
obj	#ffi_prep_cif: cif
	nargs: nargs
	rtype: rtype
	atypes: atypes
	abi: abi