support set_trace_func (incomplete. id and klass
don't be passed). And support Thread#set_trace_func
which hook only specified thread and Thread#add_trace_func
which add new trace func instead of replace old one.
C level API was modified. See thread.c (logic) and
yarvcore.h (data structures).
* vm.c, vm_macro.def: add hook points.
* compile.c, insns.def: fix "trace" instruction.
* iseq.c, vm_macro.h: add compile option "trace_instruction".
* test/ruby/test_settracefunc.rb: hook "c-return" of set_trace_func.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@12195 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
ko1