Add Xianyi's patch for segfaults on kernel 2.6.32 and add documentation

accordingly.

segfaults.patch

@@ -0,0 +1,27 @@
+From ac40907baa90a0acc78139762ffa3c6f09274236 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Alexander=20Ebersp=C3=A4cher?= <alex.eberspaecher@gmail.com>
+Date: Wed, 2 May 2012 11:22:52 +0200
+Subject: [PATCH] Fix segfaults with kernel 2.6.32. This comes at the price of many compiler warnings.
+
+---
+ common_linux.h |    4 ++--
+ 1 files changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/common_linux.h b/common_linux.h
+index b0381d9..40a94cb 100644
+--- a/common_linux.h
++++ b/common_linux.h
+@@ -76,8 +76,8 @@ static inline int my_mbind(void *addr, unsigned long len, int mode,
+ #endif
+ #else
+ //Fixed randomly SEGFAULT when nodemask==NULL with above Linux 2.6.34
+-//	unsigned long null_nodemask=0;
+-	return syscall(SYS_mbind, addr, len, mode, nodemask, maxnode, flags);
++	unsigned long null_nodemask=0;
++	return syscall(SYS_mbind, addr, len, mode, &nodemask, maxnode, flags);
+ #endif
+ }
+ 
+-- 
+1.7.1
+