Remove a few more macros from being visible to XS code

These are a few macros dealing with inversion lists that were never
intended to be visible to general XS code, and they actually can't be in
use in cpan because the mechanisms to create inversion lists are private
to perl.

Author: khwilliamson

embed.h

@@ -23,7 +23,13 @@
 
 /* When this symbol is defined, we undef various symbols we have defined
  * earlier when this file was #included with this symbol undefined */
-#if !defined(PERL_DO_UNDEFS)
+#if defined(PERL_DO_UNDEFS)
+# if !defined(PERL_CORE) && !defined(PERL_EXT)
+#   undef invlist_intersection_
+#   undef invlist_subtract_
+#   undef invlist_union_
+# endif
+#else
 
 /* Create short name macros that hide any need for thread context */
 

regen/embed.pl

@@ -3789,10 +3789,7 @@ BEGIN
     HAS_IGNORED_LOCALE_CATEGORIES_
     HIGHEST_REGCOMP_DOT_H_SYNC_
     inRANGE_helper_
-    invlist_intersection_
     invlist_intersection_complement_2nd_
-    invlist_subtract_
-    invlist_union_
     invlist_union_complement_2nd_
     is_MULTI_CHAR_FOLD_utf8_safe_part0_
     is_MULTI_CHAR_FOLD_utf8_safe_part1_