ExtUtilsTypemapsDefault: fix for perl < 5.16
ExtUtilsTypemapsDefault: fix for perl < 5.16

Add missing dependencies for ExtUtilsTypemapsDefault, needed when
building with perl < 5.16. This works for perl 5.16 too.

ExtUtils-ParseXS 3.15 has disappeared from the mirrors, so I had to bump
it to something available from CPAN; version 3.18.

See note from CPAN[1]:
  This module [ExtUtilsTypemap] exists merely as a compatibility
  wrapper around ExtUtils::Typemaps. In a nutshell, ExtUtils::Typemap
  was renamed to ExtUtils::Typemaps because the Typemap directory in
  lib/ could collide with the typemap file on case-insensitive file
  systems.

  The ExtUtils::Typemaps module is part of the ExtUtils::ParseXS
  distribution and ships with the standard library of perl starting with
  perl version 5.16.

[1] http://search.cpan.org/~smueller/ExtUtils-Typemap-1.00/lib/ExtUtils/Typemap.pm:

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