Introduce a Dockerfile for Windows

This allows one to build a Windows container for Swift.  Although it is
not perfect, it is sufficient for basic tasks.

The Git installation should preferably enable symbolic link support
which although it is marked to do does not seem to be enabled.

The Python installation should preferably set `PYTHONHOME` and
`PYTHONPATH`.  This will become increasingly important as further
refinements to the toolchain start getting merged.

Author: compnerd

5.6/windows/20H2/Dockerfile

@@ -0,0 +1,49 @@
+# escape=`
+
+FROM mcr.microsoft.com/windows/servercore:20H2 AS windows
+
+LABEL maintainer="Swift Infrastructure <[email protected]>"
+LABEL description="Docker Container for the Swift programming language"
+
+ARG GIT=https://github.com/git-for-windows/git/releases/download/v2.35.1.windows.2/Git-2.35.1.2-64-bit.exe
+ARG INSTALLER=https://download.swift.org/swift-5.6.1-release/windows10/swift-5.6.1-RELEASE/swift-5.6.1-RELEASE-windows10.exe
+ARG PYTHON=https://www.python.org/ftp/python/3.10.4/python-3.10.4-amd64.exe
+
+# restore the default Windows shell for correct batch processing
+SHELL ["cmd", "/S", "/C"]
+
+# Install Visual Studio Build Tools
+RUN                                                                             `
+  curl -SLo vs_buildtools.exe https://aka.ms/vs/17/release/vs_buildtools.exe    `
+  && (start /w vs_buildtools.exe --quiet --wait --norestart --nocache           `
+        --add Microsoft.VisualStudio.Component.Windows11SDK.22000               `
+        --add Microsoft.VisualStudio.Component.VC.Tools.x86.x64                 `
+      || IF "%EXITCODE%"=="3010" EXIT 0)                                        `
+  && del /q vs_buildtools.exe
+
+# Install Swift toolchain.
+RUN                                                                             `
+  curl -SLo installer.exe %INSTALLER%                                           `
+  && (start /w installer.exe -q)                                                `
+  && del /q installer.exe
+
+# Install Git.
+# See: git-[version]-[bit].exe /SAVEINF=git.inf and /?
+RUN                                                                             `
+  curl -SLo git.exe %GIT%                                                       `
+  && (start /w git.exe /SP- /VERYSILENT /SUPPRESSMSGBOXES /NOCANCEL /NORESTART /CLOSEAPPLICATIONS /FORCECLOSEAPPLICATIONS /NOICONS /COMPONENTS="gitlfs" /EditorOption=VIM /PathOption=Cmd /SSHOption=OpenSSH /CURLOption=WinSSL /UseCredentialManager=Enabled /PerformanceTweaksFSCache=Enabled /EnableSymlinks=Enabled /EnableFSMonitor=Enabled ) `
+  && del /q git.exe
+
+# Install Python.
+# See: https://docs.python.org/3.10/using/windows.html
+# FIXME: it appears that `PYTHONHOME` and `PYTHONPATH` are unset
+RUN                                                                             `
+  curl -SLo python.exe %PYTHON%                                                 `
+  && (start /w python.exe /quiet InstallAllUsers=1 AssociateFiles=0 PrependPath=1 Shortcuts=0 Include_doc=0 Include_debug=0 Include_dev=0 Include_exe=0 Include_launcher=0 InstallLauncherAllUsers=0 Include_lib=1 Include_pip=0 Include_symbols=0 Include_tcltk=0 Include_test=0 Include_tools=0 ) `
+  && del /q python.exe
+
+# Default to powershell
+# FIXME: we need to grant ContainerUser the SeCreateSymbolicLinkPrivilege
+# privilege so that it can create symbolic links.
+# USER ContainerUser
+CMD ["powershell.exe", "-nologo", "-ExecutionPolicy", "Bypass"]