Make _add_requirements_to_meta_* use a ref not listify hash
Use constant for default meta-spec info
Use constants to eliminate repetition in t/metafile_data.t
Specify 2.0 for META.json
Make $mm->metafile_data return hashref
Internal metadata now in 2.0 format
Make test code prettier
sprintf <<TAG bad, replaced with 'TAG'
Delete unused PM_TO_BLIB macro
Space-quote pm_to_blib args
Absolutise all typemaps because with deep-located typemaps, eg
"lib/XS/typemap", if xsubpp is called from top level with
    $(XSUBPP) ... -typemap "lib/XS/typemap" "lib/XS/Test.xs"
it says:
    Can't find lib/XS/type map in (fulldir)/lib/XS
because ExtUtils::ParseXS::process_file chdir's to .xs file's
location. This is the only way to get all specified typemaps used,
wherever located.
Sort realclean files = diff-able Makefiles
RE with interpolated filename needs quotemeta
xs_obj_opt method adds -o to all $(CCCMD) commands to put .o next to .c
Minor tidyup in makeaperl
Refactor metafile-writing to use $MM->stashmeta($text, $file)
Exportable write_file_via_tmp function, put make_type code in MM_Any
Have make_type use inheritance
Use intermediate files to store META.* and *.ppd files
Make t/meta_convert.t data-driven