lang/python37 and libuuid

[Robert Swindells <rjs%fdy2.co.uk@localhost>]

Can we make lang/python37 only use devel/libuuid/buildlink3.mk on
platforms that really need it ?

I'm guessing that this would be Linux that would require it.

The python37 package builds fine on NetBSD without including libuuid
but would fail if libuuid was installed as setup.py will find. Maybe
need some changes to the setup.py patch to change the logic around
uuid detection.

A NetBSD-8 build host would probably have installed libuuid as a
dependency of fonts/fontconfig.