In 5.21.1, C<defined(@array)> was made fatal. This has been relaxed
to not die if the argument is assigning to an array.
-=head2 Floating point handling and parsing has been improved
+=head2 Floating point parsing has been improved
Parsing and printing of floating point values has been improved.
-XXX what in addition to hexadecimal floats? if nothing, change the head2.
As a completely new feature, hexadecimal floating point literals
(like 0x1.23p-4) are now supported, and they can be output with