utf8_heavy.pl: Add 'use re "/aa"'

This would speed up compilation and execution by a trivial amount, but
makes sure that no regular expression even tries to compile in Unicode,
which could cause recursive invocation of this.  Before this construct
was invented, special care had to be taken to keep that from happening;
those measures remain in effect, but this gives added insurance.

diff --git a/lib/utf8_heavy.pl b/lib/utf8_heavy.pl
index 23e06f9..d7d4156 100644 (file)
--- a/lib/utf8_heavy.pl
+++ b/lib/utf8_heavy.pl
@@ -1,6 +1,8 @@
 package utf8;
 use strict;
 use warnings;
+use re "/aa";  # So we won't even try to look at above Latin1, potentially
+               # resulting in a recursive call
 
 sub DEBUG () { 0 }
 $|=1 if DEBUG;