--- a/test/make/UtilsForTests.gmk	Thu Feb 07 10:26:32 2019 +0100
+++ b/test/make/UtilsForTests.gmk	Thu Feb 07 12:35:45 2019 +0100
@@ -37,6 +37,6 @@
 
 # On macosx, file system timestamps only have 1 second resultion so must add
 # sleeps to properly test dependencies.
-ifeq ($(OPENJDK_BUILD_OS), macosx)
+ifeq ($(call isBuildOs, macosx), true)
   SLEEP_ON_MAC := sleep 1
 endif