adding DFSG as an approving authority

[Greg Troxel <gdt%lexort.com@localhost>]

I think this is uncontroversial at this point, but I'll wait 48h for objections.



--- license.mk.~1.90.~	2018-12-08 10:18:38.000000000 -0500
+++ license.mk	2018-12-08 10:31:22.000000000 -0500
@@ -72,6 +72,12 @@
 #	ACCEPTABLE_LICENSES; the point is to have a default that very
 #	few people want to shrink.)
 #
+#	Licenses approved by Debian as meeting the Debian Free
+#	Software Guidelines will also be added by default.  They
+#	should be in a second section with a comment about each one,
+#	because Debian does not publish an accepted license list and
+#	acceptability must be inferred from inclusion in main.
+#
 #	As an exception to the Open Source or Free policy, the board
 #	of The NetBSD Foundation has decided that licenses that
 #	trigger obligations from use (rather than redistribution),