Update Xen to 4.21

Xen 4.20 has branched.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

README

@@ -1,11 +1,11 @@
-#####################################################
-__  __            _  _    ____   ___
-\ \/ /___ _ __   | || |  |___ \ / _ \       _ __ ___
- \  // _ \ '_ \  | || |_   __) | | | |_____| '__/ __|
- /  \  __/ | | | |__   _| / __/| |_| |_____| | | (__
-/_/\_\___|_| |_|    |_|(_)_____|\___/      |_|  \___|
+############################################################
+__  __                                _        _     _
+\ \/ /___ _ __        _   _ _ __  ___| |_ __ _| |__ | | ___
+ \  // _ \ '_ \ _____| | | | '_ \/ __| __/ _` | '_ \| |/ _ \
+ /  \  __/ | | |_____| |_| | | | \__ \ || (_| | |_) | |  __/
+/_/\_\___|_| |_|      \__,_|_| |_|___/\__\__,_|_.__/|_|\___|
 
-#####################################################
+############################################################
 
 https://www.xen.org/
 

SUPPORT.md

@@ -9,7 +9,7 @@ for the definitions of the support status levels etc.
 
 # Release Support
 
-    Xen-Version: 4.20-rc
+    Xen-Version: 4.21-unstable
     Initial-Release: n/a
     Supported-Until: TBD
     Security-Support-Until: Unreleased - not yet security-supported

xen/Makefile

@@ -5,8 +5,8 @@ this-makefile := $(call lastword,$(MAKEFILE_LIST))
 # This is the correct place to edit the build version.
 # All other places this is stored (eg. compile.h) should be autogenerated.
 export XEN_VERSION       = 4
-export XEN_SUBVERSION    = 20
-export XEN_EXTRAVERSION ?= .0-rc5$(XEN_VENDORVERSION)
+export XEN_SUBVERSION    = 21
+export XEN_EXTRAVERSION ?= -unstable$(XEN_VENDORVERSION)
 export XEN_FULLVERSION   = $(XEN_VERSION).$(XEN_SUBVERSION)$(XEN_EXTRAVERSION)
 -include xen-version