How to influence the build of a .vcxproj without changing it

Question

I have the following project layout

/root/root.vcxproj
/root/submodules/library.vcxproj

Here root has a dependency on library.

Unfortunately I can't change anything in library.vcxproj. But its currently set-up to to output an .exe. Unfortunately I need it to output a static library (.lib).

I'm looking for a mechanism to influence the properties inside library.vcxproj from outside that /submodules/ directory.

Is there a trick that I can do, maybe with .props files to achieve this?

Notes: its a git submodule to a repository that I don't own. I could use a fork, but it would be harder to keep up-to-date. The vcxproj file I'm talking about is can be seen here but I don't think there's anything special in it.