Skip nethost dependency from automatic building (manual-only)

Source/Tools/Flax.Build/Deps/Dependencies/nethost.cs

@@ -41,6 +41,9 @@ namespace Flax.Deps.Dependencies
             }
         }
 
+        /// <inheritdoc />
+        public override bool BuildByDefault => false;
+
         private string root;
 
         private void Build(BuildOptions options, TargetPlatform targetPlatform, TargetArchitecture architecture)

Source/Tools/Flax.Build/Deps/Dependency.cs

@@ -51,6 +51,11 @@ namespace Flax.Deps
         /// </summary>
         public abstract TargetPlatform[] Platforms { get; }
 
+        /// <summary>
+        /// True if build dependency by default, otherwise only when explicitly specified via command line.
+        /// </summary>
+        public virtual bool BuildByDefault => true;
+
         /// <summary>
         /// Builds the dependency package using the specified options.
         /// </summary>

Source/Tools/Flax.Build/Deps/DepsBuilder.cs

@@ -62,7 +62,7 @@ namespace Flax.Deps
             {
                 var dependency = dependencies[i];
                 var name = dependency.GetType().Name;
-                if (depsToBuild.Length > 0)
+                if (depsToBuild.Length > 0 || !dependency.BuildByDefault)
                 {
                     if (!depsToBuild.Contains(name.ToLower()))
                     {