More work on getting a truly clean build

EnginePatches/EnginePatch

@@ -35,27 +35,3 @@ diff -u --recursive UnrealEngine-5.3.1-release/Engine/Source/Runtime/Application
  		// If we're rendering offscreen, use the "dummy" SDL video driver
  		if (FParse::Param(FCommandLine::Get(), TEXT("RenderOffScreen")) && !getenv("SDL_VIDEODRIVER"))
  		{
-diff -u --recursive UnrealEngine-5.3.1-release/Setup.bat UnrealEngine/Setup.bat
---- UnrealEngine-5.3.1-release/Setup.bat	2023-09-27 09:48:07.000000000 -0400
-+++ UnrealEngine/Setup.bat	2025-06-19 17:50:32.284629525 -0400
-@@ -28,7 +28,7 @@
- 
- rem Register the engine installation...
- if not exist .\Engine\Binaries\Win64\UnrealVersionSelector-Win64-Shipping.exe goto :no_unreal_version_selector
--.\Engine\Binaries\Win64\UnrealVersionSelector-Win64-Shipping.exe /register
-+.\Engine\Binaries\Win64\UnrealVersionSelector-Win64-Shipping.exe /register /unattended
- :no_unreal_version_selector
- 
- rem Done!
-diff -u --recursive UnrealEngine-5.3.1-release/Setup.sh UnrealEngine/Setup.sh
---- UnrealEngine-5.3.1-release/Setup.sh	2023-09-27 09:48:07.000000000 -0400
-+++ UnrealEngine/Setup.sh	2025-06-19 17:47:01.621969761 -0400
-@@ -80,7 +80,7 @@
- 	echo Register the engine installation...
- 	if [ -f Engine/Binaries/Linux/UnrealVersionSelector-Linux-Shipping ]; then
- 		pushd Engine/Binaries/Linux > /dev/null
--		./UnrealVersionSelector-Linux-Shipping -register > /dev/null &
-+		./UnrealVersionSelector-Linux-Shipping -register -unattended > /dev/null &
- 		popd > /dev/null
- 	fi
- 

EnginePatches/PatchedDosFiles

@@ -1 +0,0 @@
-Setup.bat

build.py

@@ -13,6 +13,10 @@ import itertools, hashlib, zipfile, fnmatch
 from pathlib import Path
 from types import SimpleNamespace
 
+#
+# Suppress an error in some of Unreal's scripts:
+#
+os.environ["GIT_DIR"] = ".git"
 
 #
 # Utility subroutines
@@ -113,34 +117,6 @@ def cpp_files_included_by(module):
     return result
 
 
-#
-# Applying patches to files with DOS line endings.
-#
-# We want to apply a patch to the UnrealEngine source, and some but not all
-# of the files we want to patch have DOS line endings.  Unfortunately, the
-# unix patch utility can't handle a codebase with mixed line endings.
-# To make it work, we convert all files to UNIX line endings, apply the
-# patch, and then convert the appropriate files back.
-#
-
-def dos2unix(fn):
-    before = Path(fn).read_bytes()
-    after = before.replace(b"\r\n", b"\n")
-    if before != after:
-        print("dos2unix ", fn)
-        Path(fn).write_bytes(after)
-
-def unix2dos(fn):
-    before = Path(fn).read_bytes()
-    after = before.replace(b"\n", b"\r\n")
-    if before != after:
-        print("unix2dos ", fn)
-        Path(fn).write_bytes(after)
-
-#
-# Given a patch file, generate a list of the files being modified.
-#
-
 #
 # Determining the build configuration.
 #
@@ -221,13 +197,10 @@ def unzip_unreal_engine_and_apply_patch():
         unrealversion = os.path.join(INTEGRATION, version)
         shutil.rmtree(UNREALENGINE, ignore_errors=True)
         shutil.rmtree(unrealversion, ignore_errors=True)
-        shell(INTEGRATION, "unzip UnrealEngine.zip")
+        print("Unzipping UnrealEngine.zip...")
+        shell(INTEGRATION, "unzip -q UnrealEngine.zip")
         patchfile = f"{INTEGRATION}/EnginePatches/EnginePatch"
-        dosfiles = Path(f"{INTEGRATION}/EnginePatches/PatchedDosFiles").read_text().splitlines()
-        dos2unix(patchfile)
-        for file in dosfiles: dos2unix(f"{unrealversion}/{file}")
         shell(unrealversion, f"patch -p1 < {patchfile}")
-        for file in dosfiles: unix2dos(f"{unrealversion}/{file}")
         Path(unrealversion).rename(UNREALENGINE)
 
 
@@ -282,13 +255,15 @@ def run_unrealengine_setup_bat_replacement():
     prompt in the middle of a build.  Yuk.  So we've written
     our own script that replaces Setup.bat/Setup.sh.
     """
-    if not Path(f"{UNREALENGINE}/Engine/Content").is_dir():
+    touch = Path(f"{UNREALENGINE}/Engine/Build/HaveGitDependencies")
+    if not touch.is_file():
         if sys.platform == "windows":
             shell(UNREALENGINE, "Engine/Binaries/DotNET/GitDependencies/win-x64/GitDependencies.exe")
             shell(UNREALENGINE, "Engine/Extras/Redist/en-us/UEPrereqSetup_x64.exe /quiet /norestart")
         else:
             shell(UNREALENGINE, "Engine/Build/BatchFiles/Linux/GitDependencies.sh")
             shell(f"{UNREALENGINE}/Engine/Build/BatchFiles/Linux", "./Setup.sh")
+        touch.write_text("Downloaded")
 
 
 def build_unrealbuildtool():