Fix missing dotnet hosting components for not yet supported platforms during projects generation stage

Source/ThirdParty/nethost/nethost.Build.cs

@@ -34,7 +34,11 @@ public class nethost : ThirdPartyModule
         if (!dotnetSdk.IsValid)
             throw new Exception($"Missing NET SDK {DotNetSdk.MinimumVersion}.");
         if (!dotnetSdk.GetHostRuntime(options.Platform.Target, options.Architecture, out var hostRuntimePath))
+        {
+            if (options.Flags.HasFlag(BuildFlags.GenerateProject))
+                return; // Ignore missing Host Runtime at projects evaluation stage (not important)
             throw new Exception($"Missing NET SDK runtime for {options.Platform.Target} {options.Architecture}.");
+        }
 
         // Setup build configuration
         switch (options.Platform.Target)

Source/Tools/Flax.Build/Build/Builder.Projects.cs

@@ -40,6 +40,7 @@ namespace Flax.Build
                         var configurationName = "Debug";
                         var configurationText = configurationName;
                         var targetBuildOptions = GetBuildOptions(target, platform, toolchain, architecture, configuration, project.WorkspaceRootPath);
+                        targetBuildOptions.Flags |= BuildFlags.GenerateProject;
                         var modules = CollectModules(rules, platform, target, targetBuildOptions, toolchain, architecture, configuration);
                         foreach (var module in modules)
                         {
@@ -65,6 +66,7 @@ namespace Flax.Build
                         configurationName = "Release";
                         configurationText = configurationName;
                         targetBuildOptions = GetBuildOptions(target, platform, toolchain, architecture, configuration, project.WorkspaceRootPath);
+                        targetBuildOptions.Flags |= BuildFlags.GenerateProject;
                         modules = CollectModules(rules, platform, target, targetBuildOptions, toolchain, architecture, configuration);
                         foreach (var module in modules)
                         {
@@ -115,6 +117,7 @@ namespace Flax.Build
 
                             var toolchain = platform.TryGetToolchain(architecture);
                             var targetBuildOptions = GetBuildOptions(target, platform, toolchain, architecture, configuration, project.WorkspaceRootPath);
+                            targetBuildOptions.Flags |= BuildFlags.GenerateProject;
                             var modules = CollectModules(rules, platform, target, targetBuildOptions, toolchain, architecture, configuration);
                             foreach (var module in modules)
                             {
@@ -275,6 +278,7 @@ namespace Flax.Build
                                         try
                                         {
                                             var referenceBuildOptions = GetBuildOptions(referenceTarget, configurationData.TargetBuildOptions.Platform, configurationData.TargetBuildOptions.Toolchain, configurationData.Architecture, configurationData.Configuration, reference.Project.ProjectFolderPath);
+                                            referenceBuildOptions.Flags |= BuildFlags.GenerateProject;
                                             var referenceModules = CollectModules(rules, referenceBuildOptions.Platform, referenceTarget, referenceBuildOptions, referenceBuildOptions.Toolchain, referenceBuildOptions.Architecture, referenceBuildOptions.Configuration);
                                             var referenceBinaryModules = GetBinaryModules(projectInfo, referenceTarget, referenceModules);
                                             foreach (var binaryModule in referenceBinaryModules)
@@ -504,6 +508,8 @@ namespace Flax.Build
                             var platform = Platform.BuildPlatform;
                             var architecture = TargetArchitecture.x64;
                             var configuration = TargetConfiguration.Debug;
+                            var buildOptions = GetBuildOptions(target, platform, null, architecture, configuration, project.WorkspaceRootPath);
+                            buildOptions.Flags |= BuildFlags.GenerateProject;
                             project.Configurations.Add(new Project.ConfigurationData
                             {
                                 Platform = platform.Target,
@@ -513,7 +519,7 @@ namespace Flax.Build
                                 Configuration = configuration,
                                 ConfigurationName = configuration.ToString(),
                                 Target = target,
-                                TargetBuildOptions = GetBuildOptions(target, platform, null, architecture, configuration, project.WorkspaceRootPath),
+                                TargetBuildOptions = buildOptions,
                                 Modules = new Dictionary<Module, BuildOptions>(),
                             });
                         }

Source/Tools/Flax.Build/Build/EngineTarget.cs

@@ -171,6 +171,7 @@ namespace Flax.Build
                 OutputFolder = mainModuleOutputPath,
                 WorkingDirectory = exeBuildOptions.WorkingDirectory,
                 HotReloadPostfix = exeBuildOptions.HotReloadPostfix,
+                Flags = exeBuildOptions.Flags,
             };
             mainModuleOptions.SourcePaths.Add(mainModule.FolderPath);
             mainModule.Setup(mainModuleOptions);

Source/Tools/Flax.Build/Build/NativeCpp/BuildOptions.cs

@@ -6,6 +6,23 @@ using System.IO;
 
 namespace Flax.Build.NativeCpp
 {
+    /// <summary>
+    /// The native C++ module build flag types.
+    /// </summary>
+    [Flags]
+    public enum BuildFlags
+    {
+        /// <summary>
+        /// Nothing.
+        /// </summary>
+        None = 0,
+
+        /// <summary>
+        /// Projects generation (not actual build, just build setup evaluation).
+        /// </summary>
+        GenerateProject = 1,
+    }
+
     /// <summary>
     /// The native C++ module build settings container.
     /// </summary>
@@ -131,6 +148,11 @@ namespace Flax.Build.NativeCpp
         /// </summary>
         public string HotReloadPostfix;
 
+        /// <summary>
+        /// The build flags.
+        /// </summary>
+        public BuildFlags Flags;
+
         /// <summary>
         /// The full path to the dependencies folder for the current build platform, configuration, and architecture.
         /// </summary>
@@ -213,7 +235,7 @@ namespace Flax.Build.NativeCpp
                 "System.Private.CoreLib",
                 "System.Private.Uri",
                 "System.Private.Xml",
-                
+
                 "System.Reflection",
                 "System.Runtime",
                 "System.Runtime.CompilerServices.Unsafe",

Source/Tools/Flax.Build/Build/NativeCpp/Builder.NativeCpp.cs

@@ -177,6 +177,7 @@ namespace Flax.Build
                     OutputFolder = outputPath,
                     WorkingDirectory = buildData.TargetOptions.WorkingDirectory,
                     HotReloadPostfix = buildData.TargetOptions.HotReloadPostfix,
+                    Flags = buildData.TargetOptions.Flags,
                 };
                 moduleOptions.SourcePaths.Add(module.FolderPath);
                 module.Setup(moduleOptions);