ImportC "no include path set"

[Elfstone]

I'm trying out ImportC, but I can't get even the "Quick Example" 
running.

     > dmd -v .\source\foobar.c
     predefs   DigitalMars LittleEndian D_Version2 all Windows 
Win32 CRuntime_Microsoft CppRuntime_Microsoft D_InlineAsm 
D_InlineAsm_X86 X86 assert D_PreConditions D_PostConditions 
D_Invariants D_ModuleInfo D_Exceptions D_TypeInfo D_HardFloat
     binary    C:\D\dmd2\windows\bin\dmd.exe
     version   v2.102.0-dirty
     config    C:\D\dmd2\windows\bin\sc.ini
     DFLAGS    -IC:\D\dmd2\windows\bin\..\..\src\phobos 
-IC:\D\dmd2\windows\bin\..\..\src\druntime\import
     include   
C:\D\dmd2\windows\bin\..\..\src\druntime\import\importc.h
     C:\Program Files\Microsoft Visual 
Studio\2022\Community\VC\Tools\MSVC\14.34.31933\bin\HostX64\x86\cl.exe /P /Zc:preprocessor /PD /nologo .\source\foobar.c /FIC:\D\dmd2\windows\bin\..\..\src\druntime\import\importc.h /Fifoobar.i
     .\source\foobar.c(1): fatal error C1034: stdio.h: no include 
path set
     Error: C preprocess command C:\Program Files\Microsoft Visual 
Studio\2022\Community\VC\Tools\MSVC\14.34.31933\bin\HostX64\x86\cl.exe failed for file .\source\foobar.c, exit status 2

So how am I supposed to set the include path?

When ran on VS' Command Prompt it spits a link error instead.

     foobar.obj : error LNK2019: unresolved external symbol 
__va_start referenced in function _fwprintf_l
     foobar.exe : fatal error LNK1120: 1 unresolved externals
     Error: linker exited with status 1120

What am I missing?