Implement 'func-arity'

* src/eval.c (Ffunc_arity, lambda_arity): New functions.
* src/bytecode.c (get_byte_code_arity): New function.
* src/lisp.h (get_byte_code_arity): Add prototype.

* doc/lispref/functions.texi (What Is a Function): Document
'func-arity'.

* etc/NEWS: Mention 'func-arity'.

* test/src/fns-tests.el (fns-tests-func-arity): New test set.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/lisp.h b/src/lisp.h
index e606ffa0259..7c8b452dd5f 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -4215,6 +4215,7 @@ extern struct byte_stack *byte_stack_list;
 extern void relocate_byte_stack (void);
 extern Lisp_Object exec_byte_code (Lisp_Object, Lisp_Object, Lisp_Object,
                                    Lisp_Object, ptrdiff_t, Lisp_Object *);
+extern Lisp_Object get_byte_code_arity (Lisp_Object);
 
 /* Defined in macros.c.  */
 extern void init_macros (void);