Since the watch branch is now merged into master, it doesn't quite build cleanly on non-linux systems anymore. So here's a small change to the Makefile to work around the problem for now. 
From 707cb47744775c324060febe11987db5f10ed9ff Mon Sep 17 00:00:00 2001
From: Jimmy Tang 
Date: Mon, 18 Jun 2012 09:20:35 +0100
Subject: [PATCH] Teach _Makefile_ to only do _-DWITH_INOTIFY_ when on a Linux
 machine.

---
 Makefile |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 6d36e8b..8884b5c 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,12 @@
+OS:=$(shell uname | sed 's/[-_].*//')
+
+ifeq ($(OS),Linux)
+BASEFLAGS_OPTS+=-DWITH_INOTIFY
+endif
+
 PREFIX=/usr
 IGNORE=-ignore-package monads-fd -ignore-package monads-tf
-BASEFLAGS=-Wall $(IGNORE) -outputdir tmp -IUtility -DWITH_S3 -DWITH_INOTIFY
+BASEFLAGS=-Wall $(IGNORE) -outputdir tmp -IUtility -DWITH_S3 $(BASEFLAGS_OPTS)
 GHCFLAGS=-O2 $(BASEFLAGS)
 
 ifdef PROFILE
-- 
1.7.10.4
[[done]], thanks --[[Joey]]