Add venv and sdist targets.

Makefile

@@ -1,6 +1,6 @@
 include src/options.mk
 
-PYTHON = python
+PYTHON = python3
 
 # Checking Python version
 PYTHON_EXE := $(shell command -v $(PYTHON) 2> /dev/null)
@@ -17,11 +17,15 @@ ifneq ($(shell test $(PYTHON_VERSION_MAJOR) -ge 3 -a $(PYTHON_VERSION_MINOR) -ge
 endif
 
 
-.PHONY: venv doc
+.PHONY: pybinding venv doc
+
+
+pybinding:
+	@+$(MAKE) -C src pybinding
 
 
 venv:
-	virtualenv --python=python$(PYTHON_VERSION_MAJOR).$(PYTHON_VERSION_MINOR) --system-site-packages --prompt="(msspec-$(VERSION)) " venv
+	virtualenv --python=$(PYTHON_EXE) --prompt="(msspec-$(VERSION)) " venv
 	. ./venv/bin/activate && pip install --upgrade pip && pip install -r src/pip.freeze
 
 doc:

src/Makefile

@@ -1,6 +1,15 @@
 include options.mk
 
-.PHONY: pybinding results clean 
+.PHONY: sdist pybinding results clean 
+
+install: sdist
+	@echo "Installing msspec python package"
+	@pip install dist/msspec-*.tar.gz
+
+sdist: pybinding
+	@echo "Creating Python source distribution..."
+	@python setup.py sdist
+
 
 pybinding:
 	@echo "Building Python binding for phagen and spec..."