diff --git a/Makefile b/Makefile
index d59ca1d6..e1b8bac1 100644
--- a/Makefile
+++ b/Makefile
@@ -16,6 +16,7 @@ OBJS += libs/sha1/sha1.o
 OBJS += libs/subcircuit/subcircuit.o
 
 GENFILES =
+EXTRA_TARGETS =
 TARGETS = yosys yosys-config
 
 all: top-all
@@ -60,7 +61,7 @@ include passes/*/Makefile.inc
 include backends/*/Makefile.inc
 include techlibs/Makefile.inc
 
-top-all: $(TARGETS)
+top-all: $(TARGETS) $(EXTRA_TARGETS)
 
 yosys: $(OBJS)
 	$(CXX) -o yosys $(LDFLAGS) $(OBJS) $(LDLIBS)
diff --git a/techlibs/Makefile.inc b/techlibs/Makefile.inc
index 031a4ad3..6c2a5f66 100644
--- a/techlibs/Makefile.inc
+++ b/techlibs/Makefile.inc
@@ -1,5 +1,5 @@
 
-TARGETS += techlibs/blackbox.v
+EXTRA_TARGETS += techlibs/blackbox.v
 
 techlibs/blackbox.v: techlibs/blackbox.sed techlibs/simlib.v techlibs/stdcells_sim.v
 	cat techlibs/simlib.v techlibs/stdcells_sim.v | sed -rf techlibs/blackbox.sed > techlibs/blackbox.v.new