--- old/make/lib/Lib-java.instrument.gmk	2019-02-05 15:45:15.614734091 +0100
+++ new/make/lib/Lib-java.instrument.gmk	2019-02-05 15:45:15.430734090 +0100
@@ -30,7 +30,7 @@
 
 ################################################################################
 
-ifeq ($(OPENJDK_TARGET_OS), windows)
+ifeq ($(call isTargetOs, windows), true)
   # equivalent of strcasecmp is stricmp on Windows
   LIBINSTRUMENT_CFLAGS := -Dstrcasecmp=stricmp
   WINDOWS_JLI_LIB := $(SUPPORT_OUTPUTDIR)/native/java.base/libjli/jli.lib
@@ -62,7 +62,7 @@
         $(WINDOWS_JLI_LIB), \
 ))
 
-ifeq ($(OPENJDK_TARGET_OS), aix)
+ifeq ($(call isTargetOs, aix), true)
   $(BUILD_LIBINSTRUMENT): $(call FindStaticLib, java.base, jli_static)
 else
   $(BUILD_LIBINSTRUMENT): $(call FindLib, java.base, jli)