diff --git a/org.alloytools.pardinus.native/native-code/Makefile b/org.alloytools.pardinus.native/native-code/Makefile
index e9bf0705e..491de35b1 100644
--- a/org.alloytools.pardinus.native/native-code/Makefile
+++ b/org.alloytools.pardinus.native/native-code/Makefile
@@ -2,10 +2,15 @@
 # On a mac (amd64/arm64) just type make in this directory
 # All native code will end up in ../native/OS/ARCH. OS=[darwin,linux,windows], ARCH=[amd64,arm64]
 #
+ifdef ComSpec
+    PS=;
+else
+    PS=:
+endif
 
 DIRS = native/linux/amd64 native/windows/amd64 native/darwin/amd64 native/darwin/arm64
 REPOS= minisat glucose lingeling minisatprover
-CLASSPATH = ../target/classes:../../org.alloytools.pardinus.core/target/classes
+CLASSPATH = ../target/classes${PS}../../org.alloytools.pardinus.core/target/classes
 
 REPOS_PATHS = $(addsuffix /repo/.git/config,$(REPOS))