setup: "make" now defaults to "simple-build", which depends on build-deps

This is for conformance with the simple new install.html.  People who don't want build-deps can run "make build".

Makefile

@@ -1,7 +1,7 @@
 
 # this Makefile requires GNU make
 
-default: build
+default: simple-build
 
 PYTHON=python
 PATHSEP=$(shell python -c 'import os ; print os.pathsep')
@@ -72,6 +72,8 @@ make-version:
 	$(MAKE) build
 	touch .built
 
+simple-build: build-deps build
+
 build: 
 	$(PYTHON) ./setup.py build_ext -i $(INCLUDE_DIRS_ARG) $(LIBRARY_DIRS_ARG)
 	chmod +x bin/tahoe