Add support for experimental .NET builds (GDExtension) (#136)

This is eventually meant to be unified with the "classical" builds,
but for the initial testing we start with a dedicated "dotnet" build.

Co-authored-by: Raul Santos <raulsntos@gmail.com>

build-dotnet/build.sh

@@ -0,0 +1,71 @@
+#!/bin/bash
+
+set -e
+
+if [ "${DOTNET}" != "1" ]; then
+  exit 0
+fi
+
+dnf install -y clang python-unversioned-command
+
+git clone https://github.com/raulsntos/godot-dotnet
+cd godot-dotnet
+git checkout upgrade-assistant-plus-source-code-plugin-wip
+
+echo "Building and generating .NET extension..."
+
+# TODO: Get rid of this when we fix all these trimming warnings in godot-dotnet.
+cat << EOF >> .editorconfig
+# Disable trimming warnings because it spams the output too much.
+dotnet_diagnostics.IL2111.severity = none
+EOF
+
+prerelease_label="${GODOT_VERSION#*-}"
+version_prefix="${GODOT_VERSION%-*}"
+
+if [[ "${prerelease_label}" == "${GODOT_VERSION}" ]]; then
+  prerelease_label=""
+fi
+
+# TODO: Ensure we don't accidentally make stable releases. We can remove this when we're ready for a stable release.
+if [[ -z "$prerelease_label" ]]; then
+  echo "YOU ARE NOT SUPPOSED TO MAKE A STABLE RELEASE WITH THIS"
+  exit -1
+fi
+
+version_component_count=$(grep -o "\." <<< "$version_prefix" | wc -l)
+
+if [ "$version_component_count" -eq 0 ]; then
+  version_prefix="${version_prefix}.0.0"
+elif [ "$version_component_count" -eq 1 ]; then
+  version_prefix="${version_prefix}.0"
+fi
+
+if [[ -n "$prerelease_label" ]]; then
+  if [[ "$prerelease_label" =~ ^dev ]]; then
+    prerelease_label="${prerelease_label/dev/alpha}"
+  fi
+
+  prerelease_label=$(echo "$prerelease_label" | sed -E 's/([^0-9])([0-9])/\1.\2/g')
+fi
+
+echo "Building Godot .NET version ${version_prefix} (prerelease: '${prerelease_label}')"
+
+dotnet --info
+
+build_id="$(date +%Y%m%d).1"
+final_version_kind="release"
+if [[ -n "$prerelease_label" ]]; then
+  final_version_kind="prerelease"
+fi
+
+./build.sh --productBuild --ci --warnAsError false \
+    /p:GenerateGodotBindings=true \
+    /p:VersionPrefix=${version_prefix} \
+    /p:OfficialBuildId=${build_id} \
+    /p:FinalVersionKind=${final_version_kind} \
+    /p:PreReleaseVersionLabel=${prerelease_label}
+
+cp -r artifacts/packages/Release/Shipping/* /root/out/
+
+echo ".NET bindings generated successfully"