diff --git a/Makefile b/Makefile
index a43f378e1..2d80c7027 100644
--- a/Makefile
+++ b/Makefile
@@ -21,6 +21,7 @@ INSTALL_SUDO :=
 EXE =
 OBJS =
 GENFILES =
+EXTRA_OBJS =
 EXTRA_TARGETS =
 TARGETS = yosys$(EXE) yosys-config
 
@@ -294,7 +295,7 @@ manual: $(TARGETS) $(EXTRA_TARGETS)
 clean:
 	rm -rf share
 	cd manual && bash clean.sh
-	rm -f $(OBJS) $(GENFILES) $(TARGETS) $(EXTRA_TARGETS)
+	rm -f $(OBJS) $(GENFILES) $(TARGETS) $(EXTRA_TARGETS) $(EXTRA_OBJS)
 	rm -f kernel/version_*.o kernel/version_*.cc abc/abc-[0-9a-f]*
 	rm -f libs/*/*.d frontends/*/*.d passes/*/*.d backends/*/*.d kernel/*.d techlibs/*/*.d
 
@@ -323,6 +324,7 @@ ifeq ($(ENABLE_ABC),1)
 endif
 	echo -en 'This is Yosys $(YOSYS_VER) for Win32.\r\n' > yosys-win32-$(YOSYS_VER)/readme.txt
 	echo -en 'Documentation at http://www.clifford.at/yosys/.\r\n' >> yosys-win32-$(YOSYS_VER)/readme.txt
+	zip yosys-win32-$(YOSYS_VER)/genfiles.zip $(GENFILES)
 	zip -r yosys-win32-$(YOSYS_VER).zip yosys-win32-$(YOSYS_VER)/
 endif
 
diff --git a/passes/techmap/Makefile.inc b/passes/techmap/Makefile.inc
index 9152ff22d..56083ed2b 100644
--- a/passes/techmap/Makefile.inc
+++ b/passes/techmap/Makefile.inc
@@ -24,7 +24,7 @@ passes/techmap/techmap.inc: techlibs/common/techmap.v
 passes/techmap/techmap.o: passes/techmap/techmap.inc
 
 TARGETS += yosys-filterlib$(EXE)
-GENFILES += passes/techmap/filterlib.o
+EXTRA_OBJS += passes/techmap/filterlib.o
 
 yosys-filterlib$(EXE): passes/techmap/filterlib.o
 	$(P) $(CXX) -o yosys-filterlib$(EXE) $(LDFLAGS) $^ $(LDLIBS)