Bug#787453: libdata-alias-perl: FTBFS with perl 5.22

[Zefram]

The compiler-dependent problem turned out to be some C-level undefined
behaviour in the module, with insufficient sequence points around a
variable mutation.  The compilers differed in whether they performed
the write before or after a call to a Perl core function (yylex())
that in 5.22 has come to depend on the variable more than it used to.

Fixed in Data-Alias-1.20, now on CPAN.

-zefram