Add fix to build UBT itself

build.py

@@ -11,7 +11,7 @@
 #   - Applies patch to Unreal Engine source.
 #   - Runs Setup.sh in the UnrealEngine repository
 #   - Builds luprex
-#   - Builds ShaderCompileWorker
+#   - Builds Unreal Build Tool and Shader Compile Worker
 #   - Builds Unreal Engine and Unreal Editor
 #   - Builds integration
 #
@@ -240,14 +240,11 @@ def generate_integration_code_workspace_ubt():
     workspace.rename(workspace_ubt)
 
 
-def build_shadercompileworker():
+def build_unrealbuildtool():
     """
-    I have no idea why shadercompileworker isn't built automatically by
-    unreal's build system, but we have to do this separately.
+    Build the unreal build tool itself, also including shader compile worker.
     """
-    shell(UNREALENGINE, f"{UNREALENGINE}/Engine/Build/BatchFiles/{BUILD_BAT} -waitmutex ShaderCompileWorker {OS} Shipping")
-    Path(f"Engine/Binaries/{OS}/ShaderCompileWorker{DOT_EXE}").unlink(missing_ok=True)
-    shutil.copyfile(f"{UNREALENGINE}/Engine/Binaries/{OS}/ShaderCompileWorker-{OS}-Shipping{DOT_EXE}", f"{UNREALENGINE}/Engine/Binaries/{OS}/ShaderCompileWorker{DOT_EXE}")
+    shell(UNREALENGINE, f"{UNREALENGINE}/Engine/Build/BatchFiles/{BUILD_BAT} -buildubt ShaderCompileWorker {OS} Development")
 
 
 def build_luprex_and_integration():
@@ -315,13 +312,16 @@ CONFIG = autodetect_system_config()
 store_system_config_in_globals(CONFIG)
 os.chdir(f"{INTEGRATION}/EnginePatches")
 
+if MODE == "experiment":
+    build_unrealbuildtool()
+
 if MODE == "all":
     generate_buildconfiguration_xml()
     generate_lpx_paths()
     patch_unrealengine_source_code()
     generate_integration_uproject()
     run_unrealengine_setup_bat()
-    build_shadercompileworker()
+    build_unrealbuildtool()
 
 if MODE in ["all", "c++"]:
     build_luprex_and_integration()