diff --git a/CHANGES/10366.packaging b/CHANGES/10366.packaging
new file mode 100644
index 00000000000..f0e9f62095a
--- /dev/null
+++ b/CHANGES/10366.packaging
@@ -0,0 +1,2 @@
+Added missing files to the source distribution to fix ``Makefile`` targets.
+Added a ``cythonize-nodeps`` target to run Cython without invoking pip to install dependencies.
diff --git a/MANIFEST.in b/MANIFEST.in
index d7c5cef6aad..64cee139a1f 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -7,6 +7,7 @@ graft aiohttp
 graft docs
 graft examples
 graft tests
+graft tools
 graft requirements
 recursive-include vendor *
 global-include aiohttp *.pyi
diff --git a/Makefile b/Makefile
index b0a3ef3226b..c6193fea9e4 100644
--- a/Makefile
+++ b/Makefile
@@ -81,6 +81,9 @@ generate-llhttp: .llhttp-gen
 .PHONY: cythonize
 cythonize: .install-cython $(PYXS:.pyx=.c) aiohttp/_websocket/reader_c.c
 
+.PHONY: cythonize-nodeps
+cythonize-nodeps: $(PYXS:.pyx=.c) aiohttp/_websocket/reader_c.c
+
 .install-deps: .install-cython $(PYXS:.pyx=.c) aiohttp/_websocket/reader_c.c $(call to-hash,$(CYS) $(REQS))
 	@python -m pip install -r requirements/dev.in -c requirements/dev.txt
 	@touch .install-deps
diff --git a/tools/gen.py b/tools/gen.py
index ab2b39a2df0..24fb71bdd9d 100755
--- a/tools/gen.py
+++ b/tools/gen.py
@@ -7,7 +7,7 @@
 import multidict
 
 ROOT = pathlib.Path.cwd()
-while ROOT.parent != ROOT and not (ROOT / ".git").exists():
+while ROOT.parent != ROOT and not (ROOT / "pyproject.toml").exists():
     ROOT = ROOT.parent