diff --git a/sys/unix/hints/macosx10.10 b/sys/unix/hints/macosx10.10
index 222690349..19737f0c1 100644
--- a/sys/unix/hints/macosx10.10
+++ b/sys/unix/hints/macosx10.10
@@ -5,11 +5,15 @@
 #
 #-PRE
 # Mac OS X (Darwin) hints file
-# This is for Mac OS X 10.10 or later.  If this doesn't work for some other
+# This is for Mac OS X 10.10 or later, and has been tested on 10.11
+# (El Capitan). If this doesn't work for some other
 # version of Mac OS X, make a new file for that OS, don't change this one.
 # And let us know about it.
 # Useful info: http://www.opensource.apple.com/darwinsource/index.html
 
+# You'll need to obtain and install XQuartz if you want X11 support.
+# (Attempting to run X11.app will describe where to get it.)
+
 # This hints file can build several different types of installations.
 # Edit the next section to match the type of build you need.
 
@@ -100,6 +104,8 @@ LFLAGS=-L/opt/X11/lib
 VARDATND = x11tiles NetHack.ad pet_mark.xbm pilemark.xbm
 POSTINSTALL+= bdftopcf win/X11/nh10.bdf > $(HACKDIR)/nh10.pcf; (cd $(HACKDIR); mkfontdir);
 CFLAGS += -DX11_GRAPHICS -I/opt/X11/include
+# avoid repeated complaints about _X_NONNULL(args...) in <X11/Xfuncproto.h>
+CFLAGS += -Wno-variadic-macros
 endif	# WANT_WIN_X11
 
 ifdef WANT_WIN_QT