diff --git a/Formula/muscle.rb b/Formula/muscle.rb
index fcd1754fd9..cf304d589d 100644
--- a/Formula/muscle.rb
+++ b/Formula/muscle.rb
@@ -6,6 +6,12 @@ class Muscle < Formula
   version '3.8.31'
   sha1 '2fe55db73ff4e7ac6d4ca692f8f213d1c5071dac'
 
+  # This patch makes 3.8.31 build on Lion.
+  # It has been reported upstream but not fixed yet.
+  def patches
+    DATA
+  end
+
   def install
     cd "src" do
       system "make"
@@ -13,3 +19,20 @@ class Muscle < Formula
     end
   end
 end
+
+__END__
+diff -Naur muscle3.8.31/src/globalsosx.cpp muscle3.8.31-patch/src/globalsosx.cpp
+--- muscle3.8.31/src/globalsosx.cpp	2010-04-29 01:43:42.000000000 +0200
++++ muscle3.8.31-patch/src/globalsosx.cpp	2012-05-07 21:17:57.000000000 +0200
+@@ -13,10 +13,10 @@
+ #include <netinet/icmp6.h>
+ #include <sys/vmmeter.h>
+ #include <sys/proc.h>
++#include <mach/vm_statistics.h>
+ #include <mach/task_info.h>
+ #include <mach/task.h>
+ #include <mach/mach_init.h>
+-#include <mach/vm_statistics.h>
+ 
+ const double DEFAULT_RAM = 1e9;
+ const double DEFAULT_MEM_USE = 1e6;