perlapi: Tighten strictures against using undocumented things

We didn't actually say that undocumented global variables and macros are
off-limits.

diff --git a/autodoc.pl b/autodoc.pl
index bd06803..2bcf263 100644 (file)
--- a/autodoc.pl
+++ b/autodoc.pl
@@ -371,13 +371,15 @@ This file contains the documentation of the perl public API generated by
 F<embed.pl>, specifically a listing of functions, macros, flags, and variables
 that may be used by extension writers.  L<At the end|/Undocumented functions>
 is a list of functions which have yet to be documented.  The interfaces of
-those are subject to change without notice.  Any functions not listed here are
+those are subject to change without notice.  Anything not listed here is
 not part of the public API, and should not be used by extension writers at
 all.  For these reasons, blindly using functions listed in proto.h is to be
 avoided when writing extensions.
 
 Note that all Perl API global variables must be referenced with the C<PL_>
-prefix.  Some macros are provided for compatibility with the older,
+prefix.  Again, those not listed here are not to be used by extension writers,
+and can be changed or removed without notice; same with macros.
+Some macros are provided for compatibility with the older,
 unadorned names, but this support may be disabled in a future release.
 
 Perl was originally written to handle US-ASCII only (that is characters