https://issues.dlang.org/show_bug.cgi?id=23193
--- Comment #5 from Walter Bright <bugzi...@digitalmars.com> --- Let's start with a `makefile` with the following contents: ----- HOST_DMD=e:\dmd2.092\windows\bin\dmd.exe all: make HOST_DMD=$(HOST_DMD) -f win32.mak clean: make HOST_DMD=$(HOST_DMD) -f win32.mak clean ----- Let's try it out: ----- make clean del lib\druntime.lib errno_c_32omf.obj Could Not Find C:\forks\druntime\lib\druntime.lib Could Not Find C:\forks\druntime\errno_c_32omf.obj rmdir /S /Q doc import The system cannot find the file specified. The system cannot find the file specified. ----- ok. Now let's try a build: ---- C:\forks\druntime>make make HOST_DMD=e:\dmd2.092\windows\bin\dmd.exe -f win32.mak "make" -f mak/WINDOWS import DMD="..\dmd\generated\windows\release\32\dmd" HOST_DMD="e:\dmd2.092\windows\bin\d md.exe" MODEL=32 IMPDIR="import" ..\dmd\generated\windows\release\32\dmd -conf= -c -o- -Isrc -Iimport -Hfimport\core\sync\barrier.di src\core\s ync\barrier.d ..\dmd\generated\windows\release\32\dmd -conf= -c -o- -Isrc -Iimport -Hfimport\core\sync\condition.di src\core \sync\condition.d ..\dmd\generated\windows\release\32\dmd -conf= -c -o- -Isrc -Iimport -Hfimport\core\sync\config.di src\core\sy nc\config.d ..\dmd\generated\windows\release\32\dmd -conf= -c -o- -Isrc -Iimport -Hfimport\core\sync\exception.di src\core \sync\exception.d ..\dmd\generated\windows\release\32\dmd -conf= -c -o- -Isrc -Iimport -Hfimport\core\sync\mutex.di src\core\syn c\mutex.d ..\dmd\generated\windows\release\32\dmd -conf= -c -o- -Isrc -Iimport -Hfimport\core\sync\rwmutex.di src\core\s ync\rwmutex.d ..\dmd\generated\windows\release\32\dmd -conf= -c -o- -Isrc -Iimport -Hfimport\core\sync\semaphore.di src\core \sync\semaphore.d "make" -f mak/WINDOWS copydir DMD="..\dmd\generated\windows\release\32\dmd" HOST_DMD="e:\dmd2.092\windows\bin\ dmd.exe" MODEL=32 IMPDIR="import" Target 'copydir' is up to date "make" -f mak/WINDOWS copy DMD="..\dmd\generated\windows\release\32\dmd" HOST_DMD="e:\dmd2.092\windows\bin\dmd .exe" MODEL=32 IMPDIR="import" if not exist generated md generated if not exist generated\windows md generated\windows if exist "../../release-build/dmd-2.079.0/windows/bin/dmd.exe" (echo @"../../release-build/dmd-2.079.0/windows /bin/dmd.exe" %* >generated\windows\host_dmd.bat) if not "" == "" ("\dmd2\Windows\bin\dmd.exe" --version >nul 2>&1 && echo @"\dmd2\Windows\bin\dmd.exe" %* >gen erated\windows\host_dmd.bat) if not "" == "" ("" --version >nul 2>&1 && echo @"" %* >generated\windows\host_dmd.bat) if not "e:\dmd2.092\windows\bin\dmd.exe" == "" ("e:\dmd2.092\windows\bin\dmd.exe" --version >nul 2>&1 && echo @"e:\dmd2.092\windows\bin\dmd.exe" %* >generated\windows\host_dmd.bat) generated\windows\host_dmd.bat -of=generated\windows\copyimports.exe -m32 mak\copyimports.d if not exist generated md generated if not exist generated\windows md generated\windows if exist "../../release-build/dmd-2.079.0/windows/bin/dmd.exe" (echo @"../../release-build/dmd-2.079.0/windows /bin/dmd.exe" %* >generated\windows\host_dmd.bat) Error: command line too long --- errorlevel 1 --- errorlevel 1 ---------- Well, that crashed and burned. As you can see, it only partly created the import directory (no import\core\stdc): --- C:\forks\druntime>dir import Volume in drive C has no label. Volume Serial Number is 6E3B-6D44 Directory of C:\forks\druntime\import 06/18/2022 11:52 PM <DIR> .. 06/18/2022 11:52 PM <DIR> core 06/18/2022 11:52 PM <DIR> . 0 File(s) 0 bytes 3 Dir(s) 209,004,240,896 bytes free C:\forks\druntime>dir import\core Volume in drive C has no label. Volume Serial Number is 6E3B-6D44 Directory of C:\forks\druntime\import\core 06/18/2022 11:52 PM <DIR> .. 06/18/2022 11:52 PM <DIR> . 06/18/2022 11:52 PM <DIR> sync 0 File(s) 0 bytes 3 Dir(s) 209,002,799,104 bytes free --- --