Add CROSS and ROOTFS_DIR environment for ARM

build_projects/dotnet-host-build/CompileTargets.cs

@@ -164,6 +164,7 @@ public static BuildTargetResult CompileCoreHost(BuildTargetContext c)
             var configuration = c.BuildContext.Get<string>("Configuration");
             string rid = c.BuildContext.Get<string>("TargetRID");
             string platform = c.BuildContext.Get<string>("Platform");
+            string crossEnv = c.BuildContext.Get<string>("Cross");
 
             // Generate build files
             var cmakeOut = Path.Combine(Dirs.CorehostLatest, "cmake");
@@ -306,6 +307,11 @@ public static BuildTargetResult CompileCoreHost(BuildTargetContext c)
                 buildScriptArgList.Add("--commithash");
                 buildScriptArgList.Add(commitHash);
 
+                if (string.Equals(crossEnv, "1"))
+                {
+                    buildScriptArgList.Add("--cross");
+                }
+
                 ExecIn(cmakeOut, buildScriptFile, buildScriptArgList);
 
                 // Copy the output out

build_projects/dotnet-host-build/PrepareTargets.cs

@@ -59,16 +59,29 @@ public static BuildTargetResult Init(BuildTargetContext c)
                 configEnv = "Debug";
             }
 
+            string crossEnv = Environment.GetEnvironmentVariable("CROSS") ?? "0";
+            if (string.Equals(crossEnv, "1"))
+            {
+                string rootfsDir = Environment.GetEnvironmentVariable("ROOTFS_DIR");
+                if (string.IsNullOrEmpty(rootfsDir))
+                {
+                    rootfsDir = Path.Combine(Dirs.RepoRoot, "cross", "rootfs", platformEnv);
+                    Environment.SetEnvironmentVariable("ROOTFS_DIR", rootfsDir);
+                }
+            }
+
             c.BuildContext["Configuration"] = configEnv;
             c.BuildContext["Channel"] = Environment.GetEnvironmentVariable("CHANNEL");
             c.BuildContext["Platform"] = platformEnv;
             c.BuildContext["TargetRID"] = targetRID;
             c.BuildContext["TargetFramework"] = targetFramework;
+            c.BuildContext["Cross"] = crossEnv;
 
             c.Info($"Building {c.BuildContext["Configuration"]} to: {Dirs.Output}");
             c.Info("Build Environment:");
             c.Info($" Operating System: {RuntimeEnvironment.OperatingSystem} {RuntimeEnvironment.OperatingSystemVersion}");
             c.Info($" Platform: " + platformEnv);
+            c.Info($" Cross Build: " + int.Parse(crossEnv));
 
             return c.Success();
         }