sstate: Improve funciton checksums

Now that bitbake is recursing into pre/postfuncs, we need to ensure
the dependencies of these functions is correct. We don't want dependencies
on MACHINE or other related variables. This patch adds in appropriate
variable exclusions to achieve this.

(From OE-Core rev: 8461283a648d7c5affd51971ebd9b35a8a4c625f)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/sstate.bbclass

@@ -211,6 +211,8 @@ def sstate_install(ss, d):
     for lock in locks:
         bb.utils.unlockfile(lock)
 
+sstate_install[vardepsexclude] = "SSTATE_DUPWHITELIST STATE_MANMACH SSTATE_MANFILEPREFIX"
+
 def sstate_installpkg(ss, d):
     import oe.path
     import subprocess
@@ -373,6 +375,8 @@ def sstate_clean(ss, d):
                 stfile.endswith(rm_nohash):
             oe.path.remove(stfile)
 
+sstate_clean[vardepsexclude] = "SSTATE_MANFILEPREFIX"
+
 CLEANFUNCS += "sstate_cleanall"
 
 python sstate_cleanall() {