Bug 20005 – VC++ can exists in separate BuildTools folder (not only in Community\Enterprise)

VC++ compiler (if it needed to VD) can be installed by BuildTools installer from MS. and default folder is C:\Program Files (x86)\Microsoft Visual Studio\20xx\BuildTools (not Comminuty or something) so VD should use it too not only VSINSTALLDIRECTORY 2nd (dunno how done for now, maybe next already is done): such folder can contains many SDKs with diff versions: C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\VC\Tools\MSVC\14.20.27508\ C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.21.27702 each of such folder contains own include, tools and libs. last two with diff host and guest archs - bin\Hostx64\x64 or lib\arm. every update of VS and BuildTools can delete old and add new SDK. so VD should contains option to select with SDK should be used or just "update to newest SDK" where VD will select lastest SDK from both folders (if they are exists) by number of SDK - 14.21.27702 is latest one.

to 2nd: when VD refs to some concrete SDK and on some running of VS (check at startup) can see that this SDK does not exists then VD can select latest SDK automatically

Buildtools now also supported by https://github.com/dlang/visuald/releases/tag/v0.50.1-beta1 regarding SDK version: Visual D detects SDK versions on every start similar to the VS batch vcvarsall.bat and sets environment variables accordingly and uses these for the respective settings. This makes it agnostic to updates of the Win10 SDK, but might not work when switching to older SDKs.