diff --git a/doc/manual/local.mk b/doc/manual/local.mk
index ca9af9c4a..930afa44f 100644
--- a/doc/manual/local.mk
+++ b/doc/manual/local.mk
@@ -94,7 +94,7 @@ doc/manual/generated/man1/nix3-manpages: $(d)/src/command-ref/new-cli
 	done
 	touch $@
 
-$(docdir)/manual/index.html: $(MANUAL_SRCS) $(d)/book.toml $(d)/custom.css $(d)/src/SUMMARY.md $(d)/src/command-ref/new-cli $(d)/src/command-ref/conf-file.md $(d)/src/expressions/builtins.md
+$(docdir)/manual/index.html: $(MANUAL_SRCS) $(d)/book.toml $(d)/custom.css $(d)/src/SUMMARY.md $(d)/src/command-ref/new-cli $(d)/src/command-ref/conf-file.md $(d)/src/expressions/builtins.md $(call rwildcard, $(d)/src, *.md)
 	$(trace-gen) RUST_LOG=warn mdbook build doc/manual -d $(DESTDIR)$(docdir)/manual
 
 endif