JIT compiler

JIT compiler

* lisp/emacs-lisp/jit-support.el: New file.
* src/alloc.c (make_byte_code): Remove.
(Fmake_byte_code): Rewrite.
* src/data.c (Fsubr_arity, notify_variable_watchers): Update.
* src/emacs.c (main): Call syms_of_jit, init_jit.
* src/eval.c (eval_sub, Fapply, FUNCTIONP, Ffuncall, funcall_subr)
(funcall_lambda): Update.
* src/jit.c: New file.
* src/lisp.h (struct subr_function): New struct, extracted from
Lisp_Subr.
(SUBR_MAX_ARGS): New define.
(struct Lisp_Subr): Use struct subr_function.
(COMPILED_JIT_CODE): New constant.
(DEFUN): Update.
(make_byte_code): Don't declare.
(funcall_subr): Add error_obj argument.
(syms_of_jit, init_jit, emacs_jit_compile): Declare.
* src/lread.c (read1): Use Fmake_byte_code.
* test/src/jit-tests.el: New file.