diff --git a/unix/make/Makefile.fmt b/unix/make/Makefile.fmt
index 51fbf501..3a078401 100644
--- a/unix/make/Makefile.fmt
+++ b/unix/make/Makefile.fmt
@@ -51,7 +51,7 @@ HFILES=\
 all: $(LIB)
 
 install: $(LIB)
-	test -d $(PREFIX)/man/man3 || mkdir $(PREFIX)/man/man3
+	test -d $(PREFIX)/man/man3 || mkdir -p $(PREFIX)/man/man3
 	install -m 0644 print.3 $(PREFIX)/man/man3/print.3
 	install -m 0644 fmtinstall.3 $(PREFIX)/man/man3/fmtinstall.3
 	mkdir -p $(PREFIX)/include