Replaced deprecation macros

* DECLARE_DEPRECATED_FEATURE with RBIMPL_ATTR_DEPRECATED_SINCE
* DECLARE_DEPRECATED_INTERNAL_FEATURE with RBIMPL_ATTR_INTERNAL
And moved function declarations outside both.

include/ruby/backward.h

@@ -12,60 +12,53 @@
 #include "ruby/internal/interpreter.h"
 #include "ruby/backward/2/attributes.h"
 
-#define DECLARE_DEPRECATED_FEATURE(ver, func) \
-    NORETURN(ERRORFUNC(("deprecated since "#ver), DEPRECATED(void func(void))))
+#define RBIMPL_ATTR_DEPRECATED_SINCE(ver) RBIMPL_ATTR_DEPRECATED(("since " #ver))
+#define RBIMPL_ATTR_INTERNAL() RBIMPL_ATTR_DEPRECATED(("internal function"))
 
 /* eval.c */
-DECLARE_DEPRECATED_FEATURE(2.2, rb_disable_super);
-DECLARE_DEPRECATED_FEATURE(2.2, rb_enable_super);
+RBIMPL_ATTR_DEPRECATED_SINCE(2.2) void rb_disable_super();
+RBIMPL_ATTR_DEPRECATED_SINCE(2.2) void rb_enable_super();
 
 /* hash.c */
-DECLARE_DEPRECATED_FEATURE(2.2, rb_hash_iter_lev);
-DECLARE_DEPRECATED_FEATURE(2.2, rb_hash_ifnone);
+RBIMPL_ATTR_DEPRECATED_SINCE(2.2) void rb_hash_iter_lev();
+RBIMPL_ATTR_DEPRECATED_SINCE(2.2) void rb_hash_ifnone();
 
 /* string.c */
-DECLARE_DEPRECATED_FEATURE(2.2, rb_str_associate);
-DECLARE_DEPRECATED_FEATURE(2.2, rb_str_associated);
+RBIMPL_ATTR_DEPRECATED_SINCE(2.2) void rb_str_associate();
+RBIMPL_ATTR_DEPRECATED_SINCE(2.2) void rb_str_associated();
 
 /* variable.c */
-DEPRECATED(void rb_autoload(VALUE, ID, const char*));
-
-/* vm.c */
-DECLARE_DEPRECATED_FEATURE(2.2, rb_clear_cache);
-DECLARE_DEPRECATED_FEATURE(2.2, rb_frame_pop);
-
-#define DECLARE_DEPRECATED_INTERNAL_FEATURE(func) \
-    NORETURN(ERRORFUNC(("deprecated internal function"), DEPRECATED(void func(void))))
+RBIMPL_ATTR_DEPRECATED_SINCE(2.5) void rb_autoload();
 
 /* eval.c */
-NORETURN(ERRORFUNC(("internal function"), void rb_frozen_class_p(VALUE)));
-DECLARE_DEPRECATED_INTERNAL_FEATURE(rb_exec_end_proc);
+RBIMPL_ATTR_INTERNAL() RBIMPL_ATTR_DEPRECATED_SINCE(2.6) void rb_frozen_class_p();
+RBIMPL_ATTR_INTERNAL() RBIMPL_ATTR_DEPRECATED_SINCE(2.7) void rb_exec_end_proc();
 
 /* error.c */
-DECLARE_DEPRECATED_INTERNAL_FEATURE(rb_compile_error);
-DECLARE_DEPRECATED_INTERNAL_FEATURE(rb_compile_error_with_enc);
-DECLARE_DEPRECATED_INTERNAL_FEATURE(rb_compile_error_append);
+RBIMPL_ATTR_INTERNAL() RBIMPL_ATTR_DEPRECATED_SINCE(2.3) void rb_compile_error();
+RBIMPL_ATTR_INTERNAL() RBIMPL_ATTR_DEPRECATED_SINCE(2.3) void rb_compile_error_with_enc();
+RBIMPL_ATTR_INTERNAL() RBIMPL_ATTR_DEPRECATED_SINCE(2.3) void rb_compile_error_append();
 
 /* gc.c */
-DECLARE_DEPRECATED_INTERNAL_FEATURE(rb_gc_call_finalizer_at_exit);
+RBIMPL_ATTR_INTERNAL() RBIMPL_ATTR_DEPRECATED_SINCE(2.7) void rb_gc_call_finalizer_at_exit();
 
 /* signal.c */
-DECLARE_DEPRECATED_INTERNAL_FEATURE(rb_trap_exit);
+RBIMPL_ATTR_INTERNAL() RBIMPL_ATTR_DEPRECATED_SINCE(2.7) void rb_trap_exit();
 
 /* struct.c */
-DECLARE_DEPRECATED_INTERNAL_FEATURE(rb_struct_ptr);
+RBIMPL_ATTR_INTERNAL() RBIMPL_ATTR_DEPRECATED_SINCE(2.4) void rb_struct_ptr();
 
 /* thread.c */
-DECLARE_DEPRECATED_INTERNAL_FEATURE(rb_clear_trace_func);
+RBIMPL_ATTR_INTERNAL() RBIMPL_ATTR_DEPRECATED_SINCE(2.7) void rb_clear_trace_func();
 
 /* variable.c */
-DECLARE_DEPRECATED_INTERNAL_FEATURE(rb_generic_ivar_table);
-NORETURN(ERRORFUNC(("internal function"), VALUE rb_mod_const_missing(VALUE, VALUE)));
+RBIMPL_ATTR_INTERNAL() RBIMPL_ATTR_DEPRECATED_SINCE(2.7) void rb_generic_ivar_table();
+RBIMPL_ATTR_INTERNAL() RBIMPL_ATTR_DEPRECATED_SINCE(2.6) VALUE rb_mod_const_missing(VALUE, VALUE);
 
 /* from version.c */
 #if defined(RUBY_SHOW_COPYRIGHT_TO_DIE) && !!(RUBY_SHOW_COPYRIGHT_TO_DIE+0)
 /* for source code backward compatibility */
-RBIMPL_ATTR_DEPRECATED(("since 2.4"))
+RBIMPL_ATTR_DEPRECATED_SINCE(2.4)
 static inline int
 ruby_show_copyright_to_die(int exitcode)
 {