in x64 mode, run:
dmd -m64 winsamp -L-Subsystem:Windows user32.lib -v
get:
D:\apps\Microsoft\2017\buildtool\VC\Tools\MSVC\14.10.25017\bin\HostX64\x64\link.exe /NOLOGO winsamp /DEFAULTLIB:"user32.lib" -Subsystem:Windows /OPT:NOICF /LIBPATH:"D:\apps\Microsoft\2017\buildtool\VC\Tools\MSVC\14.10.25017\lib\amd64" /LIBPATH:"C:\Program Files (x86)\Windows Kits\10\\lib\x64" /LIBPATH:"C:\Program Files (x86)\Windows Kits\10\\lib\10.0.14393.0\ucrt\x64" legacy_stdio_definitions.lib
There is no amd64 dir in vs2017, f.e.
D:\apps\Microsoft\2017\buildtool\VC\Tools\MSVC\14.10.25017\lib\amd64
shoudl be
D:\apps\Microsoft\2017\buildtool\VC\Tools\MSVC\14.10.25017\lib\x64
and link.d:257
if (global.params.is64bit)
cmdbuf.writestring("\\lib\\amd64\"");
should be x64
It seems there is a need to add LIBPATH just like LIB in sc.ini.