Update to v5.8 kernel headers.

Kernel headers coming from:

Git: https://android.googlesource.com/kernel/common/
Branch: android-mainline
Tag: android-mainline-5.8

Test: NA
Change-Id: I2231c877589820fc09800a200cf4ac62ba74b04c
diff --git a/libc/kernel/uapi/linux/xattr.h b/libc/kernel/uapi/linux/xattr.h
index 7c098f4..fd02159 100644
--- a/libc/kernel/uapi/linux/xattr.h
+++ b/libc/kernel/uapi/linux/xattr.h
@@ -30,6 +30,8 @@
 #define XATTR_MAC_OSX_PREFIX_LEN (sizeof(XATTR_MAC_OSX_PREFIX) - 1)
 #define XATTR_BTRFS_PREFIX "btrfs."
 #define XATTR_BTRFS_PREFIX_LEN (sizeof(XATTR_BTRFS_PREFIX) - 1)
+#define XATTR_HURD_PREFIX "gnu."
+#define XATTR_HURD_PREFIX_LEN (sizeof(XATTR_HURD_PREFIX) - 1)
 #define XATTR_SECURITY_PREFIX "security."
 #define XATTR_SECURITY_PREFIX_LEN (sizeof(XATTR_SECURITY_PREFIX) - 1)
 #define XATTR_SYSTEM_PREFIX "system."