on windows does not make any change.

C:\Perl\bin>set PERL_SIGNALS=unsafe
C:\Perl\bin>perl -e"$SIG{ALRM} = sub{die}; alarm(1); $re = ('a*' x80).
+'(b|c)'; $str = 'a' x 80;$str =~ /$re/;"
[download]

does not finish.