VS: Fix Fortran target type selection when linking C++ targets
Since commit 2c9f35789d (VS: Decide project type by linker lang as
fallback, 2017-03-30, v3.9.0-rc1~340^2) we consider the linker language
when detecting whether to generate a `.vfproj` or `.vcxproj` file.
However, this could cause C-only projects to become `.vfproj` files if
they link to Fortran projects. Instead we should consider only the
`LINKER_LANGUAGE` property on the target itself. This approach is
already used for CSharp. It allows project code to specify the project
file type for a target with no sources but does not allow linked targets
to affect it.
Fixes: #18687
2 files changed
