build fails with latest mruby

[ppibburr]

RString has changed.

I made some changes and had gotten it to build, however, CFunc::call segfaults, i had only made changes concerning s->member ie (s->as.heap.member)

[masuidrive]

Sure, I'll try to fix it.

[donpdonp]

this looks like a very useful mrbgem, but mruby build fails when including mruby-cfunc. this is from current mruby head.

CC    build/mrbgems/mruby-cfunc/src/cfunc_closure.c -> build/host/mrbgems/mruby-cfunc/src/cfunc_closure.o
In file included from /home/donp/code/neur0n/mruby/build/mrbgems/mruby-cfunc/include/cfunc_closure.h:10:0,
                 from /home/donp/code/neur0n/mruby/build/mrbgems/mruby-cfunc/src/cfunc_closure.c:7:
/home/donp/code/neur0n/mruby/build/mrbgems/mruby-cfunc/include/cfunc.h: In function ‘cfunc_state’:
/home/donp/code/neur0n/mruby/build/mrbgems/mruby-cfunc/include/cfunc.h:61:23: error: implicit declaration of function ‘mrb_object’ [-Werror=implicit-function-declaration]
         obj = (struct RClass*) mrb_object(mrb_vm_const_get(mrb, mrb_intern_cstr(mrb, "CFunc")));