diff --git a/Makefile b/Makefile
index f35d0a5f1915114088e66719387ed10736b74786..ee396100afc140f89c42cda1d7d73ddb276fbdc9 100644
--- a/Makefile
+++ b/Makefile
@@ -52,8 +52,14 @@ else
 export CL_SOURCE_REGISTRY = ${ASDF_DEVEL_SOURCE_REGISTRY}
 endif
 else # no ASDF_DEVEL_SOURCE_REGISTRY
-export CL_SOURCE_REGISTRY = ${sourceDirectory}/:${sourceDirectory}/uiop/:${sourceDirectory}/ext//:
+export CL_SOURCE_REGISTRY = ${sourceDirectory}/:${sourceDirectory}/uiop/:${sourceDirectory}/ext//
 endif
+#$(error "CL_SOURCE_REGISTRY is ${CL_SOURCE_REGISTRY}")
+sys := $(shell uname -o)
+ifeq ($(sys),Cygwin) 
+CL_SOURCE_REGISTRY := $(shell cygpath -pw "${CL_SOURCE_REGISTRY}")
+endif
+
 
 l ?= sbcl
 
@@ -76,6 +82,8 @@ driver_lisp := uiop/package.lisp uiop/common-lisp.lisp uiop/utility.lisp uiop/os
 defsystem_lisp := upgrade.lisp component.lisp system.lisp cache.lisp find-system.lisp find-component.lisp operation.lisp action.lisp lisp-action.lisp plan.lisp operate.lisp output-translations.lisp source-registry.lisp parse-defsystem.lisp bundle.lisp concatenate-source.lisp package-inferred-system.lisp backward-internals.lisp backward-interface.lisp interface.lisp user.lisp footer.lisp
 all_lisp := $(header_lisp) $(driver_lisp) $(defsystem_lisp)
 
+print-%  : ; @echo $* = $($*)
+
 # Making ASDF itself should be our first, default, target:
 build/asdf.lisp: $(all_lisp)
 	mkdir -p build