diff --git a/prism/ext/lpsolve55/Makefile b/prism/ext/lpsolve55/Makefile
index 79f3871f..f50fade4 100644
--- a/prism/ext/lpsolve55/Makefile
+++ b/prism/ext/lpsolve55/Makefile
@@ -33,12 +33,13 @@ checks:
 	fi; 
 
 ../../lib/$(LIBPREFIX)lpsolve55$(LIBSUFFIX):
+	mkdir -p lib
 	@(if [ "$(OSTYPE)" = "cygwin" ]; then \
 	  cp bin/$(BINDISTSUFFIX)/$(LIBPREFIX)lpsolve55$(LIBSUFFIX) ../../lib; \
 	else \
 	  (cd src/lp_solve_5.5/lpsolve55 && \
 	  ARCH=$(ARCH) c=$(C) sh -x $(LPSOLVE55_BUILD) \
-	  ) && mv lib/$(LIBPREFIX)lpsolve55$(LIBSUFFIX) ../../lib; \
+	  ) && mv lib/$(LIBPREFIX)lpsolve55$(LIBSUFFIX) ../../lib/; \
 	fi)
 
 clean: checks