Windows + LDC/DMD installation nightmare when changing VS versions

[Guillaume Piolat]

Originally I installed VisualD and LDC and DMD with the VisualD 
installer on top of VS2019 and life was good.

Then because VS2019 is very slow, I uninstalled VS2019 and 
installed VS2015 instead.
This broke both DMD+64-bit and LDC despite having LDC_VSDIR set 
at "invalid-path". Isn't it supposed to auto-detect? Well it 
wasn't anymore and LINK.EXE would not get found.

I then reinstalled stuff with the VisualD installer, which fixed 
DMD + 64-bit (Linking stage was never finishing) but not LDC + 
32-bit.


Now:
- With DMD + 64-bit it works.
- With DMD + 32-bit it works.
- With LDC + 64-bit it works.
- With LDC + 32-bit it still fail with:

   libcmt.lib(chkstk.obj) : fatal error LNK1112: module machine 
type 'X86' conflicts with target machine type 'x64'
   Error: C:\Program Files (x86)\Microsoft Visual Studio 
14.0\VC\BIN\link.exe failed with status: 1112
   ldc2 failed with exit code 1.
   error: Command 'dub build --build=debug --arch=x86_64 
--compiler=ldc2 --config=VST-FULL' returned 2


Any idea what could be causing this?

Please help. This was a living nightmare. I just want a working 
setup...