diff --git a/recipes/hostpython.py b/recipes/hostpython.py
new file mode 100644
index 0000000..3291cc3
--- /dev/null
+++ b/recipes/hostpython.py
@@ -0,0 +1,15 @@
+# -*- coding: utf-8 -*-
+from toolchain import Recipe
+
+class HostpythonAliasRecipe(Recipe):
+    is_alias = True
+
+    def init_after_import(self, ctx):
+        hostpython = ctx.state.get("hostpython")
+        if not hostpython:
+            print("WARNING: no hostpython set yet, so you need to specify")
+            print("WARNING: either hostpython2 or hostpython3 in your deps")
+        else:
+            self.depends = [hostpython]
+
+recipe = HostpythonAliasRecipe()
diff --git a/recipes/hostpython2/__init__.py b/recipes/hostpython2/__init__.py
index 3281a00..bccb7e8 100644
--- a/recipes/hostpython2/__init__.py
+++ b/recipes/hostpython2/__init__.py
@@ -5,7 +5,7 @@ import sh
 import shutil
 
 
-class HostpythonRecipe(Recipe):
+class Hostpython2Recipe(Recipe):
     version = "2.7.1"
     url = "https://www.python.org/ftp/python/{version}/Python-{version}.tar.bz2"
     depends = ["hostlibffi"]
@@ -13,7 +13,9 @@ class HostpythonRecipe(Recipe):
     archs = ["x86_64"]
 
     def init_with_ctx(self, ctx):
-        super(HostpythonRecipe, self).init_with_ctx(ctx)
+        super(Hostpython2Recipe, self).init_with_ctx(ctx)
+        self.set_hostpython(self, 2.7)
+        self.ctx.so_suffix = ".so"
         self.ctx.hostpython = join(self.ctx.dist_dir, "hostpython", "bin", "python")
         self.ctx.hostpgen = join(self.ctx.dist_dir, "hostpython", "bin", "pgen")
         print("Global: hostpython located at {}".format(self.ctx.hostpython))
@@ -110,4 +112,4 @@ class HostpythonRecipe(Recipe):
             join(self.ctx.dist_dir, "hostpython", "bin", "pgen"))
 
 
-recipe = HostpythonRecipe()
+recipe = Hostpython2Recipe()
diff --git a/recipes/hostpython3/__init__.py b/recipes/hostpython3/__init__.py
index 7d99b86..740dcc9 100644
--- a/recipes/hostpython3/__init__.py
+++ b/recipes/hostpython3/__init__.py
@@ -14,6 +14,8 @@ class Hostpython3Recipe(Recipe):
 
     def init_with_ctx(self, ctx):
         super(Hostpython3Recipe, self).init_with_ctx(ctx)
+        self.set_hostpython(self, 3.7)
+        self.ctx.so_suffix = ".cpython-37m-darwin.so"
         self.ctx.hostpython = join(self.ctx.dist_dir, "hostpython3", "bin", "python")
         self.ctx.hostpgen = join(self.ctx.dist_dir, "hostpython3", "bin", "pgen")
         print("Global: hostpython located at {}".format(self.ctx.hostpython))
diff --git a/recipes/ios/__init__.py b/recipes/ios/__init__.py
index af4264d..33a6678 100644
--- a/recipes/ios/__init__.py
+++ b/recipes/ios/__init__.py
@@ -9,9 +9,8 @@ class IosRecipe(CythonRecipe):
     pbx_frameworks = ["MessageUI", "CoreMotion", "UIKit"]
 
     def install(self):
-        self.install_python_package(name="ios.so", is_dir=False)
+        self.install_python_package(
+            name=self.so_filename("ios"), is_dir=False)
 
 
 recipe = IosRecipe()
-
-
diff --git a/recipes/kivy/__init__.py b/recipes/kivy/__init__.py
index 9b9b19d..559e1df 100644
--- a/recipes/kivy/__init__.py
+++ b/recipes/kivy/__init__.py
@@ -6,8 +6,8 @@ class KivyRecipe(CythonRecipe):
     version = "1.10.1"
     url = "https://github.com/kivy/kivy/archive/{version}.zip"
     library = "libkivy.a"
-    depends = ["python", "sdl2", "sdl2_image", "sdl2_mixer", "sdl2_ttf", "ios",
-               "pyobjus"]
+    depends = ["sdl2", "sdl2_image", "sdl2_mixer", "sdl2_ttf", "ios",
+               "pyobjus", "python"]
     pbx_frameworks = ["OpenGLES", "Accelerate"]
     pre_build_ext = True
 
@@ -40,4 +40,3 @@ class KivyRecipe(CythonRecipe):
 
 
 recipe = KivyRecipe()
-
diff --git a/recipes/pyobjus/__init__.py b/recipes/pyobjus/__init__.py
index 639b838..210aad4 100644
--- a/recipes/pyobjus/__init__.py
+++ b/recipes/pyobjus/__init__.py
@@ -18,8 +18,9 @@ class PyobjusRecipe(CythonRecipe):
 
     def cythonize_build(self):
         # don't use the cythonize, pyobjus don't support method rewriting
+        pyver = "-{}".format(self.ctx.python_major)
         shprint(sh.find, self.build_dir, "-iname", "*.pyx",
-                "-exec", "cython", "{}", ";")
+                "-exec", "cython", pyver, "{}", ";")
         # ffi is installed somewhere else, this include doesn't work
         # XXX ideally, we need to fix libffi installation...
         shprint(sh.sed,
@@ -28,5 +29,3 @@ class PyobjusRecipe(CythonRecipe):
                 "pyobjus/pyobjus.c")
 
 recipe = PyobjusRecipe()
-
-
diff --git a/recipes/python.py b/recipes/python.py
new file mode 100644
index 0000000..359f03f
--- /dev/null
+++ b/recipes/python.py
@@ -0,0 +1,15 @@
+# -*- coding: utf-8 -*-
+from toolchain import Recipe
+
+class PythonAliasRecipe(Recipe):
+    is_alias = True
+
+    def init_after_import(self, ctx):
+        python = ctx.state.get("python")
+        if not python:
+            print("WARNING: no python set yet, so you need to specify")
+            print("WARNING: either python2 or python3 in your deps")
+        else:
+            self.depends = [python]
+
+recipe = PythonAliasRecipe()
diff --git a/recipes/python2/__init__.py b/recipes/python2/__init__.py
index 24cde16..ac253e6 100644
--- a/recipes/python2/__init__.py
+++ b/recipes/python2/__init__.py
@@ -4,21 +4,21 @@ import sh
 import os
 
 
-class PythonRecipe(Recipe):
+class Python2Recipe(Recipe):
     version = "2.7.1"
     url = "https://www.python.org/ftp/python/{version}/Python-{version}.tar.bz2"
-    depends = ["hostpython", "libffi", ]
+    depends = ["hostpython2", "libffi"]
     optional_depends = ["openssl"]
     library = "libpython2.7.a"
     pbx_libraries = ["libz", "libbz2", "libsqlite3"]
 
     def init_with_ctx(self, ctx):
-        super(PythonRecipe, self).init_with_ctx(ctx)
-        self.ctx.python_ver_dir = "python2.7"
-        self.ctx.python_prefix = join(ctx.dist_dir, "root", "python")
-        self.ctx.site_packages_dir = join(
-            ctx.dist_dir, "root", "python", "lib", ctx.python_ver_dir,
-            "site-packages")
+        super(Python2Recipe, self).init_with_ctx(ctx)
+        self.set_python(self, 2.7)
+        ctx.python_ver_dir = "python2.7"
+        ctx.python_prefix = join(ctx.dist_dir, "root", "python")
+        ctx.site_packages_dir = join(
+            ctx.python_prefix, "lib", ctx.python_ver_dir, "site-packages")
 
     def prebuild_arch(self, arch):
         # common to all archs
@@ -149,4 +149,4 @@ class PythonRecipe(Recipe):
             os.chdir(oldpwd)
 
 
-recipe = PythonRecipe()
+recipe = Python2Recipe()
diff --git a/recipes/python3/__init__.py b/recipes/python3/__init__.py
index 41ae1d1..0ad068a 100644
--- a/recipes/python3/__init__.py
+++ b/recipes/python3/__init__.py
@@ -15,11 +15,11 @@ class Python3Recipe(Recipe):
 
     def init_with_ctx(self, ctx):
         super(Python3Recipe, self).init_with_ctx(ctx)
-        self.ctx.python_ver_dir = "python3.7"
-        self.ctx.python_prefix = join(ctx.dist_dir, "root", "python")
-        self.ctx.site_packages_dir = join(
-            ctx.dist_dir, "root", "python", "lib", ctx.python_ver_dir,
-            "site-packages")
+        self.set_python(self, 3.7)
+        ctx.python_ver_dir = "python3.7"
+        ctx.python_prefix = join(ctx.dist_dir, "root", "python3")
+        ctx.site_packages_dir = join(
+            ctx.python_prefix, "lib", ctx.python_ver_dir, "site-packages")
 
     def prebuild_arch(self, arch):
         # common to all archs
diff --git a/toolchain.py b/toolchain.py
index 80a3961..922f85f 100755
--- a/toolchain.py
+++ b/toolchain.py
@@ -306,6 +306,7 @@ class Context(object):
     cython = None
     sdkver = None
     sdksimver = None
+    so_suffix = None  # set by one of the hostpython
 
     def __init__(self):
         super(Context, self).__init__()
@@ -413,20 +414,30 @@ class Context(object):
         return "IDEBuildOperationMaxNumberOfConcurrentCompileTasks={}".format(self.num_cores)
 
 
+
 class Recipe(object):
-    version = None
-    url = None
-    archs = []
-    depends = []
-    optional_depends = []
-    library = None
-    libraries = []
-    include_dir = None
-    include_per_arch = False
-    frameworks = []
-    sources = []
-    pbx_frameworks = []
-    pbx_libraries = []
+    props = {
+        "is_alias": False,
+        "version": None,
+        "url": None,
+        "archs": [],
+        "depends": [],
+        "optional_depends": [],
+        "library": None,
+        "libraries": [],
+        "include_dir": None,
+        "include_per_arch": False,
+        "frameworks": [],
+        "sources": [],
+        "pbx_frameworks": [],
+        "pbx_libraries": []
+    }
+
+    def __new__(cls):
+        for prop, value in cls.props.items():
+            if not hasattr(cls, prop):
+                setattr(cls, prop, value)
+        return super(Recipe, cls).__new__(cls)
 
     # API available for recipes
     def download_file(self, url, filename, cwd=None):
@@ -560,6 +571,12 @@ class Recipe(object):
         """
         return join(self.ctx.include_dir, "common", self.name)
 
+    def so_filename(self, name):
+        """Return the filename of a library with the appropriate so suffix
+        (.so for Python 2.7, .cpython-37m-darwin for Python 3.7)
+        """
+        return "{}{}".format(name, self.ctx.so_suffix)
+
     @property
     def name(self):
         modname = self.__class__.__module__
@@ -619,6 +636,37 @@ class Recipe(object):
             arch = self.filtered_archs[0]
         return arch.get_env()
 
+    def set_hostpython(self, instance, version):
+        state = self.ctx.state
+        hostpython = state.get("hostpython")
+        if hostpython is None:
+            state["hostpython"] = instance.name
+            state.sync()
+        elif hostpython != instance.name:
+            print("ERROR: Wanted to use {}".format(instance.name))
+            print("ERROR: but hostpython is already provided by {}.".format(
+                hostpython))
+            print("ERROR: You can have only one hostpython version compiled")
+            sys.exit(1)
+        self.ctx.python_major = int(version)
+        self.ctx.hostpython_ver = version
+        self.ctx.hostpython_recipe = instance
+
+    def set_python(self, instance, version):
+        state = self.ctx.state
+        python = state.get("python")
+        if python is None:
+            state["python"] = instance.name
+            state.sync()
+        elif python != instance.name:
+            print("ERROR: Wanted to use {}".format(instance.name))
+            print("ERROR: but python is already provided by {}.".format(
+                python))
+            print("ERROR: You can have only one python version compiled")
+            sys.exit(1)
+        self.ctx.python_ver = version
+        self.ctx.python_recipe = instance
+
     @property
     def archive_root(self):
         key = "{}.archive_root".format(self.name)
@@ -649,6 +697,12 @@ class Recipe(object):
             raise ValueError("Invalid path passed into {}".format(envname))
         return d
 
+    def init_after_import(cls, ctx):
+        """This can be used to dynamically set some variables
+        depending of the state
+        """
+        pass
+
     @cache_execution
     def download(self):
         key = "{}.archive_root".format(self.name)
@@ -875,6 +929,7 @@ class Recipe(object):
             mod = importlib.import_module("recipes.{}".format(name))
             recipe = mod.recipe
             recipe.recipe_dir = join(ctx.root_dir, "recipes", name)
+            recipe.init_after_import(ctx)
 
         if version:
             recipe.version = version
@@ -916,7 +971,7 @@ class PythonRecipe(Recipe):
                 "--prefix", iosbuild,
                 _env=env)
         dest_dir = join(self.ctx.site_packages_dir, name)
-        self.remove_junk(iosbuild)
+        #self.remove_junk(iosbuild)
         if is_dir:
             if exists(dest_dir):
                 shutil.rmtree(dest_dir)
@@ -944,6 +999,7 @@ class CythonRecipe(PythonRecipe):
             filename = filename[len(self.build_dir) + 1:]
         print("Cythonize {}".format(filename))
         cmd = sh.Command(join(self.ctx.root_dir, "tools", "cythonize.py"))
+        hostpython = self.ctx.state.get("hostpython")
         shprint(cmd, filename)
 
     def cythonize_build(self):
@@ -1021,6 +1077,9 @@ def build_recipes(names, ctx):
     build_order = list(graph.find_order())
     print("Build order is {}".format(build_order))
     recipes = [Recipe.get_recipe(name, ctx) for name in build_order]
+    recipes = [recipe for recipe in recipes if not recipe.is_alias]
+    recipes_order = [recipe.name for recipe in recipes]
+    print("Recipe order is {}".format(recipes_order))
     for recipe in recipes:
         recipe.init_with_ctx(ctx)
     for recipe in recipes: