Packages the distutils stdlib module as a standalone package,
```
377K distutils.data
221K distutils.data.br
19K distutils.js
```
to reduce the minimal pyodide size.

Part of #1542 

This also,
 - adds documentation on what's supported or not in the stdlib
 - makes a few changes to `pyodide_build/buildall.py` to be able to add such stdlib packages as a dependency in other packages (which didn't work before). For instance, until there is a release with https://github.com/pypa/packaging/pull/396 micropip has a dependency on distutils.
Unvendor distutils. Packages the distutils stdlib module as a standalone package,
```
377K distutils.data
221K distutils.data.br
19K distutils.js
```
to reduce the minimal pyodide size.

Part of #1542 

This also,
 - adds documentation on what's supported or not in the stdlib
 - makes a few changes to `pyodide_build/buildall.py` to be able to add such stdlib packages as a dependency in other packages (which didn't work before). For instance, until there is a release with https://github.com/pypa/packaging/pull/396 micropip has a dependency on distutils.
From f78bb95d3c95a4fb20745eb70ad876495de26e94 Mon Sep 17 00:00:00 2001
From: Michael Droettboom <mdboom@gmail.com>
Date: Sun, 5 Jul 2020 17:37:43 +0200
Subject: [PATCH] disable-set_inheritable


diff --git a/Python/fileutils.c b/Python/fileutils.c
index e79e732d1f..864dc78a57 100644
--- a/Python/fileutils.c
+++ b/Python/fileutils.c
@@ -1091,6 +1091,9 @@ _Py_get_inheritable(int fd)
 static int
 set_inheritable(int fd, int inheritable, int raise, int *atomic_flag_works)
 {
+#ifdef EMSCRIPTEN
+    return 0;
+#endif
 #ifdef MS_WINDOWS
     HANDLE handle;
     DWORD flags;

From f78bb95d3c95a4fb20745eb70ad876495de26e94 Mon Sep 17 00:00:00 2001
From: Michael Droettboom <mdboom@gmail.com>
Date: Sun, 5 Jul 2020 17:37:43 +0200
Subject: [PATCH] disable-set_inheritable


diff --git a/Python/fileutils.c b/Python/fileutils.c
index e79e732d1f..864dc78a57 100644
--- a/Python/fileutils.c
+++ b/Python/fileutils.c
@@ -1091,6 +1091,9 @@ _Py_get_inheritable(int fd)
 static int
 set_inheritable(int fd, int inheritable, int raise, int *atomic_flag_works)
 {
+#ifdef EMSCRIPTEN
+    return 0;
+#endif
 #ifdef MS_WINDOWS
     HANDLE handle;
     DWORD flags;
