Merge "Clarify what's in the upstream- directories..." into main
diff --git a/README.md b/README.md
index 9a44934..32dda04 100644
--- a/README.md
+++ b/README.md
@@ -101,10 +101,18 @@
upstream-freebsd/
upstream-netbsd/
upstream-openbsd/
- # These directories contain unmolested upstream source. Any time we can
- # just use a BSD implementation of something unmodified, we should.
- # The structure under these directories mimics the upstream tree,
- # but there's also...
+ # These directories contain upstream source with no local changes.
+ # Any time we can just use a BSD implementation of something unmodified,
+ # we should. Ideally these should probably have been three separate git
+ # projects in external/, but they're here instead mostly by historical
+ # accident (because it wouldn't have been easy to import just the tiny
+ # subset of these operating systems that -- unlike Android -- just have
+ # one huge repository rather than lots of little ones and a mechanism
+ # like our `repo` tool).
+ # The structure under these directories mimics the relevant upstream tree,
+ # but in order to actually be able to compile this code in our tree
+ # _without_ making modifications to the source files directly, we also
+ # have the following subdirectories in each one that aren't upstream:
android/
include/
# This is where we keep the hacks necessary to build BSD source