diff --git a/man/Makefile b/man/Makefile
index 4c5187a..e7fbbb3 100644
--- a/man/Makefile
+++ b/man/Makefile
@@ -1,7 +1,7 @@
 # Makefile
 
 INSTALL= install
-INSTALL_PROGRAM= $(INSTALL)
+INSTALL_PROGRAM= $(INSTALL) -c
 INSTALL_DATA= $(INSTALL) -m 644
 GROFF= groff
 
diff --git a/tools/Makefile b/tools/Makefile
index 26e7e40..fe117b3 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -10,7 +10,7 @@ clean:
 	rm -f $(TARGETS)
 	rm -f *.o
 
-INSTALL= install
+INSTALL= install -c
 INSTALL_PROGRAM= $(INSTALL)
 INSTALL_DATA= $(INSTALL) -m 644