Allow the mspdb DLL to be found via vswhere.exe

[dscho]

The incredibly useful vswhere.exe tool can be used to abstract away all the nitty-gritty details of figuring out where Visual Studio is installed.

This patch adds support for making use of that tool. If the tool is found and finds a Visual Studio, we use the corresponding path. Otherwise, we simply continue as we would have continued before this patch.

We are already using this patch in Git for Windows for quite some time, with a lot of success.

[dscho]

@rainers to verify that this works, I added a GitHub workflow. I did that in two commits: one to introduce the workflow, just building cv2pdb. And then another that uses Git for Windows' GCC to compile an .exe file and then verifies that the just-built cv2pdb can process it.

Here is the latest run: https://github.com/dscho/cv2pdb/actions/runs/1416650185.

Please let me know if you're happy to take the GitHub workflow. If not: my apologies, I did not want to sneak in an unrelated change, I only needed to make sure that my fix still works, even after modifying the patch substantially, and can easily move these two commits to a private branch.

[rainers]

@dscho LGTM, thanks for your work on this.

Github actions look quite nice, let's see how they work with cv2pdb. There is not much recent activity here, though.

[dscho]

Thank you!

[dscho]

@rainers would it be asking too much if I asked for a new tagged version? ;-)

[rainers]

@rainers would it be asking too much if I asked for a new tagged version? ;-)

Now available as https://github.com/rainers/cv2pdb/releases/tag/v0.49

[dscho]

Thank you!