Add devcontainer configurations (#4402)

Adds two devcontainer configurations:

* configuration "Docker": the default, equivalent to using run_docker 
* configuration "Conda"

Codespaces and VS Code allow users to select the configuration.

.devcontainer/conda/devcontainer.json

@@ -0,0 +1,19 @@
+{
+  "name": "Conda",
+  "image": "mcr.microsoft.com/devcontainers/base:bullseye",
+
+  // Comment out to connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root.
+  "remoteUser": "vscode",
+
+  // Setup conda environment
+  "onCreateCommand": ".devcontainer/onCreate-conda.sh",
+
+  // Install additional features.
+  "features": {
+    // For config options, see https://github.com/devcontainers/features/tree/main/src/conda
+    "ghcr.io/devcontainers/features/conda": {
+      "version": "latest",
+      "addCondaForge": "true"
+    }
+  }
+}

.devcontainer/devcontainer.json

@@ -0,0 +1,7 @@
+{
+  "name": "Docker",
+  // keep in sync with "run_docker"
+  "image": "pyodide/pyodide-env:20230506-chrome112-firefox112-py311",
+  "remoteUser": "root",
+  "onCreateCommand": ".devcontainer/onCreate-docker.sh"
+}

.devcontainer/onCreate-conda.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+
+# Do not keep running on errors
+set -ex
+
+# from https://pyodide.org/en/stable/development/building-from-sources.html#using-make:
+# - build-essential
+# we install pkg-config with apt because it is commented out in environment.yml
+sudo apt-get update && sudo apt-get install --yes build-essential pkg-config
+
+conda env create -n pyodide-env -f environment.yml
+conda init bash
+echo "conda activate pyodide-env" >> ~/.bashrc
+
+# conda run -n pyodide-env make -C emsdk clean
+# conda run -n pyodide-env make -C cpython clean
+
+# https://pyodide.org/en/stable/development/building-from-sources.html#using-docker
+export EMSDK_NUM_CORE=12 EMCC_CORES=12 PYODIDE_JOBS=12
+echo "export EMSDK_NUM_CORE=12 EMCC_CORES=12 PYODIDE_JOBS=12" >> ~/.bashrc
+echo "export PYODIDE_BUILD_TMP=/tmp/pyodide-build" >> ~/.bashrc
+
+conda run -n pyodide-env --live-stream pip install -r requirements.txt
+
+# https://pyodide.org/en/stable/development/new-packages.html#prerequisites
+conda run -n pyodide-env --live-stream pip install -e ./pyodide-build
+
+# Building emsdk and cpython takes a few minutes to run, so we do not run it here.
+#
+# conda run -n pyodide-env --live-stream make -C emsdk
+# conda run -n pyodide-env --live-stream make -C cpython

.devcontainer/onCreate-docker.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+# Do not keep running on errors
+set -e
+
+# https://pyodide.org/en/stable/development/new-packages.html#prerequisites
+pip install -e ./pyodide-build
+
+# Building emsdk and cpython takes a few minutes to run, so we do not run it here.
+#
+# make -C emsdk
+# make -C cpython

docs/development/building-from-sources.md

@@ -60,6 +60,20 @@ You can edit the files in the shared `pyodide` source folder on your host
 machine (outside of Docker), and then repeatedly run `make` inside the Docker
 environment to test your changes.
 
+### Using the "Docker" dev container
+
+We provide a dev container configuration that is equivalent to the use of
+`./run_docker` script. It can be used in [Visual Studio Code](https://code.visualstudio.com/docs/devcontainers/containers) and
+on [GitHub Codespaces](https://docs.github.com/en/codespaces/overview).
+When prompted, select "Docker".
+
+### Using the "Conda" dev container
+
+We provide another dev container configuration that corresponds to
+the "Linux with conda" method described below. When [Visual Studio Code](https://code.visualstudio.com/docs/devcontainers/containers) or
+[GitHub Codespaces](https://docs.github.com/en/codespaces/overview)
+prompts for the dev container configuration, select "Conda".
+
 ## Using `make`
 
 Make sure the prerequisites for
@@ -185,8 +199,8 @@ The following environment variables additionally impact the build:
   with a trailing `/`. Default: `./` to load Pyodide packages from the same
   base URL path as where `pyodide.js` is located. Example:
   `{{PYODIDE_CDN_URL}}`
-- `EXTRA_CFLAGS` : Add extra compilation flags.
-- `EXTRA_LDFLAGS` : Add extra linker flags.
+- `EXTRA_CFLAGS`: Add extra compilation flags.
+- `EXTRA_LDFLAGS`: Add extra linker flags.
 
 Setting `EXTRA_CFLAGS="-D DEBUG_F"` provides detailed diagnostic information
 whenever error branches are taken inside the Pyodide core code. These error