Log Message:
- Fix the build with newer ExtUtils-MakeMaker
Incompatible change in the newer ExtUtils-MakeMaker:
It places .o files where the source file lives (lib/File/ in this case),
whereas the older MakeMaker placed it in the current working dir
(toplevel in this case).

Thanks Matthias Ferdinand
http://mail-index.netbsd.org/pkgsrc-users/2015/09/19/msg022238.html