[OE-core] Python Large File System Support

[Ong, Boon Leong]

Dear all, 

Based on https://docs.python.org/2/library/posix.html, in order to support LFS in python, 
there is a special CFLAGS "-D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64" needed.

I did a search around meta/recipes-devtool/python found many recipes files.  
So, I am reaching out to expert in this forum to guide on which is the right file
to be touched to enabled LFS? 

I notice perl seems to have this supported in recipes and I believe python user would
benefit from this enabling too.

Thanks..

Ong Boon Leong