Pin manifest of pie-vts-release

Change-Id: I0bceddd1bcdf22a060147e171906053b309531ac
diff --git a/default.xml b/default.xml
index 6d828dd..a285f4f 100644
--- a/default.xml
+++ b/default.xml
@@ -4,7 +4,7 @@
   <remote fetch=".." name="aosp" review="https://android-review.googlesource.com/" />
   <default remote="aosp" revision="pie-vts-release" sync-j="4" />
 
-  <project groups="pdk" name="platform/build" path="build/make" revision="224362f42e74fac592873e0e961ee67177f7369a">
+  <project groups="pdk" name="platform/build" path="build/make" revision="ef9b71efc8212301869b4409aae40305c88dda34">
     <copyfile dest="Makefile" src="core/root.mk" />
     <linkfile dest="build/CleanSpec.mk" src="CleanSpec.mk" />
     <linkfile dest="build/buildspec.mk.default" src="buildspec.mk.default" />