[tools] Add dotnet-linker, a project to contain custom linker steps for our net5.0 build.

tools/Makefile

@@ -1,3 +1,3 @@
 TOP=..
-SUBDIRS=mmp mtouch install-source xibuild mlaunch siminstaller
+SUBDIRS=mmp mtouch install-source xibuild mlaunch siminstaller dotnet-linker
 include $(TOP)/Make.config

tools/dotnet-linker/.gitignore

@@ -0,0 +1,2 @@
+*.csproj.inc
+.vscode/

tools/dotnet-linker/Makefile

@@ -0,0 +1,42 @@
+TOP=../..
+
+include $(TOP)/Make.config
+
+PLATFORMS=iOS tvOS watchOS macOS
+
+BUILD_DIR=bin/Debug/net5.0
+
+DOTNET_TARGETS += \
+	$(BUILD_DIR)/dotnet-linker.dll \
+	$(foreach platform,$(PLATFORMS),$(DOTNET_DESTDIR)/Microsoft.$(platform).Sdk/tools/dotnet-linker/dotnet-linker.dll) \
+	$(foreach platform,$(PLATFORMS),$(DOTNET_DESTDIR)/Microsoft.$(platform).Sdk/tools/dotnet-linker/dotnet-linker.pdb) \
+
+DOTNET_DIRECTORIES += \
+	$(foreach platform,$(PLATFORMS),$(DOTNET_DESTDIR)/Microsoft.$(platform).Sdk/tools/dotnet-linker) \
+
+$(BUILD_DIR)/dotnet-linker%dll $(BUILD_DIR)/dotnet-linker%pdb: Makefile $(dotnet_linker_dependencies)
+	$(Q_DOTNET_BUILD) $(DOTNET5) build $(XBUILD_VERBOSITY)
+
+$(DOTNET_DESTDIR)/Microsoft.iOS.Sdk/tools/dotnet-linker/%: $(BUILD_DIR)/% | $(DOTNET_DESTDIR)/Microsoft.iOS.Sdk/tools/dotnet-linker
+	$(Q) $(CP) $< $@
+
+$(DOTNET_DESTDIR)/Microsoft.tvOS.Sdk/tools/dotnet-linker/%: $(BUILD_DIR)/% | $(DOTNET_DESTDIR)/Microsoft.tvOS.Sdk/tools/dotnet-linker
+	$(Q) $(CP) $< $@
+
+$(DOTNET_DESTDIR)/Microsoft.watchOS.Sdk/tools/dotnet-linker/%: $(BUILD_DIR)/% | $(DOTNET_DESTDIR)/Microsoft.watchOS.Sdk/tools/dotnet-linker
+	$(Q) $(CP) $< $@
+
+$(DOTNET_DESTDIR)/Microsoft.macOS.Sdk/tools/dotnet-linker/%: $(BUILD_DIR)/% | $(DOTNET_DESTDIR)/Microsoft.macOS.Sdk/tools/dotnet-linker
+	$(Q) $(CP) $< $@
+
+$(DOTNET_DIRECTORIES):
+	$(Q) mkdir -p $@
+
+# dotnet-linker.csproj.inc contains the dotnet_linker_dependencies variable used to determine if mtouch needs to be rebuilt or not.
+dotnet-linker.csproj.inc: export BUILD_EXECUTABLE=$(DOTNET5) build
+dotnet-linker.csproj.inc: dotnet-linker.csproj Makefile ../common/create-makefile-fragment.sh $(TOP)/Make.config $(TOP)/mk/mono.mk
+	$(Q_GEN) ../common/create-makefile-fragment.sh $(abspath $<)
+-include dotnet-linker.csproj.inc
+
+all-local:: $(DOTNET_TARGETS)
+install-local:: $(DOTNET_TARGETS)

tools/dotnet-linker/NuGet.config

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+	<config>
+		<add key="repositorypath" value="packages" />
+		<add key="globalPackagesFolder" value="packages" />
+	</config>
+	<packageSources>
+		<add key="Nuget Official" value="https://www.nuget.org/api/v2/" />
+		<add key="Dotnet arcade" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-eng/nuget/v3/index.json" />
+		<add key="dotnet5" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet5/nuget/v3/index.json" />
+	</packageSources>
+</configuration>
+

tools/dotnet-linker/SetupStep.cs

@@ -0,0 +1,14 @@
+using System;
+
+using Mono.Linker.Steps;
+
+namespace Xamarin {
+
+	public class SetupStep : BaseStep {
+
+		protected override void Process ()
+		{
+			Console.WriteLine ("Hello SetupStep");
+		}
+	}
+}

tools/dotnet-linker/dotnet-linker.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>net5.0</TargetFramework>
+    <RootNamespace>dotnet_linker</RootNamespace>
+  </PropertyGroup>
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.ILLink" Version="5.0.0-preview.3.20302.1" />
+  </ItemGroup>
+</Project>

tools/dotnet-linker/dotnet-linker.sln

@@ -0,0 +1,17 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio 15
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "dotnet-linker", "dotnet-linker.csproj", "{7F7392F4-AB2D-4153-B591-46C79501B3C6}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{7F7392F4-AB2D-4153-B591-46C79501B3C6}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{7F7392F4-AB2D-4153-B591-46C79501B3C6}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{7F7392F4-AB2D-4153-B591-46C79501B3C6}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{7F7392F4-AB2D-4153-B591-46C79501B3C6}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+EndGlobal

tools/dotnet-linker/global.json

@@ -0,0 +1,3 @@
+{
+	"sdk": { "version": "5.*" }
+}