Log message:
Pullup ticket #6352 - requested by nia
graphics/openexr: NetBSD 8 build fix

Revisions pulled up:
- graphics/openexr/buildlink3.mk                                1.16

---
   Module Name:	pkgsrc
   Committed By:	nia
   Date:		Sun Oct 18 09:52:32 UTC 2020

   Modified Files:
   	pkgsrc/graphics/openexr: buildlink3.mk

   Log message:
   openexr: Require at least gcc6 in dependent packages

   (attempt to fix dependent packages in NetBSD 8.x)