[4.0] 08e2b3a Document why this hack is needed.

[Poul-Henning Kamp]

commit 08e2b3a80049c6a16bef95b0615639e556a709fe
Author: Poul-Henning Kamp <phk at FreeBSD.org>
Date:   Wed Jan 29 09:50:27 2014 +0000

    Document why this hack is needed.

diff --git a/autogen.des b/autogen.des
index 8c2a3b2..0cbbbc0 100755
--- a/autogen.des
+++ b/autogen.des
@@ -18,6 +18,8 @@ rm -f configure
 # autoconf prior to 2.62 has issues with zsh 4.2 and newer
 export CONFIG_SHELL=/bin/sh
 
+# NB: Workaround for make distcheck not working with
+# NB: FreeBSD's make on -current
 # env MAKE=gmake \
 ./configure \
     --enable-developer-warnings \