docs: Comments on windows workflows

Add comments on the Windows workflows to cross-reference them
with each other and the new DEVELOPER_GUIDE.md docs section for Windows
builds.

Add a short note to the windows PR workflow on how to run it manually
on a forked repo when submitting patches.

Signed-off-by: Craig Ringer <[email protected]>

.github/workflows/call-build-windows.yaml

@@ -1,6 +1,16 @@
 ---
 name: Reusable workflow to build Windows packages optionally into S3 bucket
 
+#
+# If you change dependencies etc here, please also check and update
+# the other Windows build resources:
+#
+# - DEVELOPER_GUIDE.md "Windows" section
+# - appveyor.yml
+# - .github/workflows/call-build-windows.yaml
+# - dockerfiles/Dockerfile.windows
+#
+
 on:
   workflow_call:
     inputs:

.github/workflows/pr-windows-build.yaml

@@ -1,5 +1,18 @@
 name: PR - Windows checks
+
+#
+# Test PRs on Windows
+#
+# This won't run automatically on PRs from untrusted repos, it must be approved
+# manually. If PR authors want to run it themselves, they should enable running
+# actions on their fork, then invoke it on their branch via their forked repo's
+# Actions tab.
+#
+
 on:
+  # Enable invocation via Github repo Actions tab. Having this in the repo
+  # allows people with github forks to run this job on their own branches to
+  # build Windows branches conveniently. See DEVELOPER_GUIDE.md.
   workflow_dispatch:
 
   pull_request:

appveyor.yml

@@ -1,5 +1,15 @@
 version: v1-winbuild-{build}
 
+#
+# If you change dependencies etc here, please also check and update
+# the other Windows build resources:
+#
+# - DEVELOPER_GUIDE.md "Windows" section
+# - appveyor.yml
+# - .github/workflows/call-build-windows.yaml
+# - dockerfiles/Dockerfile.windows
+#
+
 image: Visual Studio 2019
 
 platform:

dockerfiles/Dockerfile.windows

@@ -1,5 +1,16 @@
 # escape=`
 
+# This Dockerfile will only build on Docker for Windows.
+#
+# If you change dependencies etc here, please also check and update
+# the other Windows build resources:
+#
+# - DEVELOPER_GUIDE.md "Windows" section
+# - appveyor.yml
+# - .github/workflows/call-build-windows.yaml
+# - dockerfiles/Dockerfile.windows
+#
+
 ARG WINDOWS_VERSION=ltsc2019
 
 # Builder Image - Windows Server Core