Python3 build support

Everything needed to build python3 and use it with our embedded par
files.

android/regen.sh uses the upstream configure & makesetup scripts, along
with the Setup.local files in order to generate the per-platform
Android-*.bp, config.c and pyconfig.h files. The android pyconfig.h is
based on the linux one, with some changes via sed.

android/launcher_main.cpp is a rewritten version our launcher_main.cpp
in our cpython2 tree, now using the new PyConfig interfaces instead of
requiring code changes to the upstream path calculation code.

The hash/ssl plugins rely on openssl upstream, and we've only got
boringssl. I'll be looking at that in a future change.

Bug: 73372094
Test: cd external/python/cpython3; mma
Test: m par_test{,3}; build/soong/python/tests/runtest.sh
Change-Id: I563f6db1bd8a45e1ffec34d5017e5a8ca54fa28e
diff --git a/Lib/Android.bp b/Lib/Android.bp
new file mode 100644
index 0000000..cd43f1d
--- /dev/null
+++ b/Lib/Android.bp
@@ -0,0 +1,42 @@
+// Copyright 2019 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+python_library {
+    name: "py3-stdlib",
+    is_internal: true,
+    pkg_path: "stdlib",
+    srcs: [
+        "*.py",
+        "collections/**/*.py",
+        "compiler/**/*.py",
+        "ctypes/**/*.py",
+        "distutils/**/*.py",
+        "email/**/*.py",
+        "encodings/**/*.py",
+        "hotshot/**/*.py",
+        "importlib/**/*.py",
+        "json/**/*.py",
+        "logging/**/*.py",
+        "multiprocessing/**/*.py",
+        "pydoc_data/**/*.py",
+        "sqlite3/**/*.py",
+        "unittest/**/*.py",
+        "wsgiref/**/*.py",
+        "xml/**/*.py",
+    ],
+    exclude_srcs: [
+        "__phello__.foo.py",
+    ],
+    host_supported: true,
+}